diff --git a/apps/app_analyze_fn.lua b/apps/app_analyze_fn.lua
deleted file mode 100644
index 2991818..0000000
--- a/apps/app_analyze_fn.lua
+++ /dev/null
@@ -1,81 +0,0 @@
-local apps   = require 'apps.apps'
-local choice = require('dialog.choice').display_sync
-local ask_n  = require('dialog.input').display_sync_n
-local sym    = require('ti.sym')
-local ui     = require('ui.shared')
-local lexer  = require 'ti.lexer'
-local expr   = require 'expressiontree'
-local sym    = require 'ti.sym'
-
-local function each_result(str, fn)
-   local tokens = lexer.tokenize(str)
-   local e = tokens and expr.from_infix(tokens)
-   if e then
-      if e.text == '{' or e.text == 'or' or e.text == 'and' then
-         for _, arg in ipairs(e:collect_operands_recursive()) do
-            fn(arg)
-         end
-      else
-         fn(e)
-      end
-   end
-end
-
-local function run_analyze(stack)
-  local fn, low, high = table.unpack(ask_n(3, { title = "Analyze ..." }))
-  local var = "x"
-
-  local with_str = nil
-  if low:len() ~= 0 then
-    with_str = (with_str and with_str .. " and ") or "|"
-    with_str = with_str .. low  .. ">=" .. var
-  end
-  if high:len() ~= 0 then
-    with_str = (with_str and with_str .. " and ") or "|"
-    with_str = with_str .. var .. "<=" .. high
-  end
-
-  local function get_zeros(fn, bounds)
-    local tab = {}
-    each_result(math.evalStr(string.format("zeros(%s,%s)%s", fn, var, bounds or "")),
-                function(z)
-                   table.insert(tab, z)
-                end)
-    return tab
-  end
-  
-  local function is_zero(fn, at)
-    return math.evalStr(string.format("(%s|%s=%s)=0", fn, var, at)) == "true"
-  end
-  
-  local function has_sign_change(fn, at, delta)
-    local delta = "0.000001"
-    local is_neg_0 = math.evalStr(string.format("(%s|%s=%s-%s)<0", fn, var, at, delta)) == "true"
-    local is_neg_1 = math.evalStr(string.format("(%s|%s=%s+%s)<0", fn, var, at, delta)) == "true"
-    if is_neg_0 ~= is_neg_1 then
-      return (not is_neg_0 and is_neg_1) and -1 or 1
-    end
-    return 0
-  end
-  
-  local results = {}
-
-  local zeros = get_zeros(fn, with_str)
-  if zeros and #zeros > 0 then
-    table.insert(results, {title="Zeros", result="*zeros"})
-    
-    for _, v in ipairs(zeros) do
-      local x = v:infix_string()
-      local y = math.evalStr(string.format("%s|%s=%s", fn, var, x))
-      table.insert(results, {title=string.format("%s=%s (%s|%s)", var, x, x, y), result=x})
-    end
-  end
-
-
-  local r = choice({
-    title = 'Results',
-    items = results
-  })
-end
-
-apps.add('analyze', 'Analyze function', run_analyze)
diff --git a/apps/app_binom.lua b/apps/app_binom.lua
deleted file mode 100644
index 39fd12f..0000000
--- a/apps/app_binom.lua
+++ /dev/null
@@ -1,97 +0,0 @@
-local apps       = require 'apps.apps'
-local ask        = require('dialog.input').display_sync
-local choice     = require('dialog.choice').display_sync
-
-local function run_find_n(stack)
-   local p = "0.50"
-   local op = ">="
-   local limit = "1"
-   local low = "0"
-   local high = "100"
-   local r_op = ">="
-   local r = "0.50"
-
-   while true do
-      local action = choice({
-         title = 'Binom - Find n - ' .. string.format('P(X%s%s)%s%s', op, limit, r_op, r),
-         items = {
-            {align = -1, title = 'p = ' .. p, result = 'p'},
-            {align = -1, title = 'X', result = 'x'},
-            {align = -1, title = op, result = 'o'},
-            {align = -1, title = limit, result = 'l'},
-            {align = -1, title = r_op, result = 'r_op'},
-            {align = -1, title = r, result = 'r'},
-            {align = -1, title = 'n low = ' .. low, result = 'low'},
-            {align = -1, title = 'n high = ' .. high, result = 'high'},
-            {align =  0, title = 'Find... ', result = 'e'},
-         }
-      })
-      if action == 'p' then
-         p = ask {title = 'p', text = p} or p
-      elseif action == 'l' or action == 'x' then
-         limit = ask {title = 'Limit', text = limit} or limit
-      elseif action == 'o' then
-         op = choice {
-            title = "Operator",
-            items = {
-               { title = "=",  result = "=" },
-               { title = ">=", result = ">=" },
-               { title = "<=", result = "<=" },
-            }
-         } or op
-      elseif action == 'r_op' then
-         r_op = choice {
-            title = "Operator",
-            items = {
-               { title = "=",  result = "=" },
-               { title = ">", result = ">" },
-               { title = ">=", result = ">=" },
-               { title = "<", result = "<" },
-               { title = "<=", result = "<=" },
-            }
-         } or r_op
-      elseif action == 'r' then
-         r = ask {title = 'r', text = r} or r
-      elseif action == 'low' then
-         low = ask {title = 'Lower bound (n)', text = low} or low
-      elseif action == 'high' then
-         high = ask {title = 'Upper bound (n)', text = high} or high
-      elseif action == 'e' then
-         break
-      else
-         return
-      end
-   end
-
-   local function eval(n)
-      local fn
-      if op == '=' then
-         fn = string.format('binomPdf(%s,%s,%s)', n, p, limit)
-      elseif op == '<=' then
-         fn = string.format('binomCdf(%s,%s,%s,%s)', n, p, 0, limit)
-      elseif op == '>=' then
-         fn = string.format('binomCdf(%s,%s,%s,%s)', n, p, limit, n)
-      end
-      return math.evalStr(fn .. r_op .. r)
-   end
-
-   low = tonumber(low) or 0
-   high = tonumber(high) or 100
-   for n = low, high do
-      local res = eval(n)
-      if res == 'true' then
-         choice{
-            title = "Results",
-            items = {
-               { title = "n = " .. tostring(n - 2) .. "; " .. eval(n - 2) },
-               { title = "n = " .. tostring(n - 1) .. "; " .. eval(n - 1) },
-               { title = "n = " .. tostring(n + 0) .. "; " .. res },
-               { title = "n = " .. tostring(n + 1) .. "; " .. eval(n + 1) },
-               { title = "n = " .. tostring(n + 2) .. "; " .. eval(n + 2) },
-            }
-         }
-      end
-   end
-end
-
-apps.add('binom - find n', 'Binom - Find n', run_find_n)
diff --git a/apps/app_punktsteigung.lua b/apps/app_punktsteigung.lua
deleted file mode 100644
index 60b4392..0000000
--- a/apps/app_punktsteigung.lua
+++ /dev/null
@@ -1,86 +0,0 @@
-local apps   = require 'apps.apps'
-local lexer  = require 'ti.lexer'
-local expr   = require 'expressiontree'
-local ask    = require('dialog.input').display_sync
-local choice = require('dialog.choice').display_sync
-
-local function eval(str, fallback)
-   return select(1, math.evalStr(str)) or fallback
-end
-
-local function each_result(str, fn)
-   local tokens = lexer.tokenize(eval(str))
-   local e = tokens and expr.from_infix(tokens)
-   if e then
-      if e.text == '{' or e.text == 'or' or e.text == 'and' then
-         for _, arg in ipairs(e:collect_operands_recursive()) do
-            fn(arg)
-         end
-      else
-         fn(e)
-      end
-   end
-end
-
-local function eval_bool(str)
-   local res = eval(str)
-   if res == 'false' then return false end
-   if res == 'true' then return true end
-end
-
-local function run_tangent(stack)
-   local fx = ask { title = 'f(x)', text = eval('f1(x)') }
-
-   local x = ask { title = 'x' }
-   local y = eval(string.format('(%s)|x=%s', fx, x))
-   local m = eval(string.format('derivative(%s,x)|x=%s', fx, x))
-   if not m then m = ask { title = 'm' } end
-
-   stack:push_infix(string.format('%s*(x-%s)+%s', m, x, y))
-end
-apps.add('tangent t(x)', 'Tangent', run_tangent)
-
-local function run_tangent_pt(stack)
-   local fx = ask { title = 'f(x)', text = eval('f1(x)') }
-   if not fx then return end
-   local pt = { x = ask { title = 'x' }, y = ask { title = 'y' } }
-   if not (pt.x and pt.y) then return end
-
-   local store = choice { title = 'Store results?', items = {
-      { title = 'As t1(x) ...', result = 'tx', seq = {'t'} },
-      { title = 'As f2(x) ...', result = 'fx', seq = {'f'} },
-      { title = 'No', result = false, seq = {'n'} },
-   }}
-
-   local fd = eval(string.format('derivative(%s,x)', fx))
-
-   local n = 1
-   each_result(string.format('solve((%s)-(%s)=(%s)*(x-(%s)),x)', fx, pt.y, fd, pt.x),
-       function(e)
-          local x = eval('right('..e:infix_string()..')')
-          local y = eval(string.format('(%s)|x=%s', fx, x))
-          local m = eval(string.format('derivative(%s,x)|x=%s', fx, x))
-          if not m then return end
-
-          local tx = string.format('%s*(x-%s)+%s', m, x, y)
-          if eval_bool(string.format('((%s)=%s)|x=%s', tx, pt.y, pt.x)) ~= false then
-             stack:push_expr(e)
-             stack:push_infix(string.format('%s*(x-%s)+%s', m, x, y))
-             if store then
-                local fn
-                if store == 'tx' then
-                   fn = string.format('t%d(x)', n)
-                elseif store == 'fx' then
-                   fn = string.format('f%d(x)', n+1)
-                end
-
-                stack:push_infix(fn)
-                stack:push_rstore()
-             end
-             n = n + 1
-          else
-             print('Skipping function')
-          end
-       end)
-end
-apps.add('tangent t(x) p(x,y)', 'Tangent through p(x,y)', run_tangent_pt)
diff --git a/apps/app_trassierung.lua b/apps/app_trassierung.lua
deleted file mode 100644
index a104bfb..0000000
--- a/apps/app_trassierung.lua
+++ /dev/null
@@ -1,55 +0,0 @@
-local apps   = require 'apps.apps'
-local ask    = require('dialog.input').display_sync
-local choice = require('dialog.choice').display_sync
-
--- Generate polynom prototype of specified degree
----@param deg number Polynom degree
----@return string
-local function gen_fn_prototype(deg, _c)
-   local alpha = { 'a', 'b', 'c', 'd', 'e', 'f' }
-   _c = _c or deg
-   if _c == 0 then return alpha[deg + 1] end
-   return alpha[deg - _c + 1] .. '*x^' .. tostring(_c) .. '+' .. gen_fn_prototype(deg, _c - 1)
-end
-
-local function run_trassierung(stack)
-   local deg = tonumber(ask { title = 'deg(g)', text = '3' })
-   if not deg then return end
-
-   local proto = ask { title = 'g(x)', text = gen_fn_prototype(deg) }
-   if not proto then return end
-
-   math.evalStr('delvar g')
-   math.evalStr(string.format('%s=:g(x)', proto))
-
-   local lo, hi = '0', '0'
-   lo = ask { title = 'low x' }
-   if not lo then return end
-   hi = ask { title = 'high x' }
-   if not hi then return end
-
-   local lofn, hifn = 'f1', 'f2'
-   lofn = ask { title = 'low fn', text = lofn }
-   if not lofn then return end
-   hifn = ask { title = 'high fn', text = hifn }
-   if not lofn then return end
-
-   local eqs = {}
-   table.insert(eqs, 'g(x)=' .. lofn .. '(x)|x=' .. lo)
-   table.insert(eqs, 'g(x)=' .. hifn .. '(x)|x=' .. hi)
-   table.insert(eqs, 'derivative(g(x),x)=' .. 'derivative(' .. lofn .. '(x),x)|x=' .. lo)
-   table.insert(eqs, 'derivative(g(x),x)=' .. 'derivative(' .. hifn .. '(x),x)|x=' .. hi)
-
-   if choice { title = '2nd diff?', items = dlg_choice.yesno } then
-      table.insert(eqs, 'derivative(derivative(g(x),x),x)=' .. 'derivative(derivative(' .. lofn .. '(x),x),x)|x=' .. lo)
-      table.insert(eqs, 'derivative(derivative(g(x),x),x)=' .. 'derivative(derivative(' .. hifn .. '(x),x),x)|x=' .. hi)
-   end
-
-   stack:push_infix('system(' .. table.concat(eqs, ',') .. ')')
-
-   if choice { title = 'solve?', items = dlg_choice.yesno } then
-      -- TODO: ...
-   end
-end
-
-apps.add('trassierung g(x)', 'Smooth join fns', run_trassierung)
diff --git a/apps/app_triangle.lua b/apps/app_triangle.lua
deleted file mode 100644
index 708072a..0000000
--- a/apps/app_triangle.lua
+++ /dev/null
@@ -1,147 +0,0 @@
-local apps       = require 'apps.apps'
-local ask        = require('dialog.input').display_sync
-local choice     = require('dialog.choice').display_sync
-local formsolver = require 'apps.formsolver'
-
-local vars_default = {
-   { 'Side a', 'a' },
-   { 'Side b', 'b' },
-   { 'Side c', 'c' },
-   { 'Alpha', 'alpha' },
-   { 'Beta', 'beta' },
-   { 'Gamma', 'gamma' },
-   { 'Perimeter', 'p' },
-   { 'Area', 'area' },
-}
-
-local vars_full = {
-   { 'Side a', 'a' },
-   { 'Side b', 'b' },
-   { 'Side c', 'c' },
-   { 'Alpha', 'alpha' },
-   { 'Beta', 'beta' },
-   { 'Gamma', 'gamma' },
-   { 'Perimeter', 'p' },
-   { 'Semiperimeter', 's' },
-   { 'Area', 'area' },
-   { 'Height a', 'ha' },
-   { 'Height b', 'hb' },
-   { 'Height c', 'hc' },
-   { 'Inradius', 'inrad' },
-   { 'Circumradius', 'circumrad' },
-}
-
-local function run_triangle(stack)
-   local vars = vars_default
-   local formulas = {
-      -- Law of sine
-      '{a}/sin({alpha})={b}/sin({beta})',
-      '{b}/sin({beta})={c}/sin({gamma})',
-      '{c}/sin({gamma})={a}/sin({alpha})',
-      -- Law of cosine
-      '{a}^2={b}^2+{c}^2-2*{b}*{c}*cos({alpha})',
-      '{b}^2={a}^2+{c}^2-2*{a}*{c}*cos({beta})',
-      '{c}^2={a}^2+{b}^2-2*{a}*{b}*cos({gamma})',
-      -- Perimeter
-      '{p}={a}+{b}+{c}',
-      '{s}={p}/2',
-      -- Area
-      '{area}=1/2*{a}*{b}*sin({gamma})',
-      '{area}=1/2*{b}*{c}*sin({alpha})',
-      '{area}=1/2*{c}*{a}*sin({beta})',
-      '{area}=sqrt({s}*({s}-{a})*({s}-{b})*({s}-{c}))',
-      -- Height
-      '{ha}=2*{area}/{a}',
-      '{hb}=2*{area}/{b}',
-      '{hc}=2*{area}/{c}',
-      -- Inradius
-      '{inrad}={area}/{s}',
-      -- Circumradius
-      '{circumrad}={a}/(2*sin({alpha}))',
-      '{circumrad}={b}/(2*sin({beta}))',
-      '{circumrad}={c}/(2*sin({gamma}))',
-   }
-
-   local mode = math.getEvalSettings()[2][1]
-   if mode == 'Radian' then
-      table.insert(formulas, '{alpha}+{beta}+{gamma}=pi')
-   else
-      table.insert(formulas, '{alpha}+{beta}+{gamma}=180')
-   end
-
-   local set = {}
-
-   local sel = 1 -- Dialog selection index
-   while true do
-      local actions = {}
-      for _, v in ipairs(vars) do
-         local name, var = v[1], v[2]
-         table.insert(actions, { name, set[var] or '', result = var })
-      end
-
-      --table.insert(actions, {'Set ABC...', '', result = 'points'})
-      if vars == vars_default then
-         table.insert(actions, { 'Show all...', '', result = 'full' })
-      end
-      table.insert(actions, { 'Solve...', '', result = 'done' })
-
-      local action
-      action, sel = choice { title = 'Triangle', items = actions, selection = sel }
-      if not action then return end
-      if action == 'done' then
-         break
-      elseif action == 'full' then
-         vars = vars_full
-      elseif action then
-         set[action] = ask { title = 'Set ' .. action, text = set[action] or '' }
-      end
-   end
-
-   local unsolved = {}
-   for _, k in ipairs(vars) do
-      k = k[2]
-      if not set[k] then
-         table.insert(unsolved, k)
-      end
-   end
-
-   -- Solve all unsolved variables
-   local steps
-   set, steps = formsolver.solve_for(unsolved, set, formulas)
-
-   sel = 1
-   while true do
-      local actions = {}
-      for _, v in ipairs(vars) do
-         local name, var = v[1], v[2]
-         table.insert(actions, { name, set[var] or '?', result = var })
-      end
-
-      table.insert(actions, { 'Steps...', '', result = 'explain' })
-      table.insert(actions, { 'Done...', '[esc]', result = 'done' })
-
-      local action
-      action, sel = choice { title = 'Result', items = actions, selection = sel }
-      if not action then return end
-      if action == 'done' then
-         break
-      elseif action == 'explain' then
-         local step_items = {}
-         for _, v in ipairs(steps) do
-            table.insert(step_items, { title = v.formula..' for '..v.var, result = v.formula })
-         end
-
-         while true do
-            action = choice { title = 'Steps', items = step_items, font_size = 9, row_size = 16 }
-            if not action then break end
-            stack:push_infix(action)
-         end
-      elseif action ~= nil then
-         stack:push_infix(set[action])
-         stack:push_infix(action)
-         stack:push_rstore()
-      end
-   end
-end
-
-apps.add('triangle', 'Triangle solver', run_triangle)
diff --git a/apps/ask_vars.lua b/apps/ask_vars.lua
deleted file mode 100644
index 77fc745..0000000
--- a/apps/ask_vars.lua
+++ /dev/null
@@ -1,79 +0,0 @@
-local choice = require('dialog.choice').display_sync
-local ask    = require('dialog.input').display_sync
-
-local t = {}
-
-local function prepare_vars(vars)
-    local new = {}
-    for k, v in pairs(vars) do
-        if type(v) ~= "table" then
-            new[k] = {value = tostring(v)}
-        else
-            new[k] = v
-        end
-
-        local item = new[k]
-        item.kind = item.kind or "text"     
-        item.options = item.options
-        item.value = item.value or "0"
-    end
-    return new
-end
-
-function t.ask_vars(vars, title)
-    title = title or "Variables"
-    vars = prepare_vars(vars)
-
-    -- Result table
-    local r = {}
-    for k, v in pairs(vars) do
-        r[k] = r[k] or v.value
-    end
-
-    -- Ask for a single value
-    local function ask_value(key)
-        local is_choice = vars[key].options ~= nil
-        if is_choice then
-            local items = {}
-            for _, v in ipairs(vars[key].options) do
-                if type(v) == "table" then
-                    table.insert(items, {title = v.title, result = v.result or v.title})
-                else
-                    table.insert(items, {title = tostring(v), result = tostring(v)})
-                end
-            end
-        
-            return choice{
-                title = key .. "...",
-                items = items,
-            } or r[key]
-        else
-            return ask{
-                title = key .. "...",
-                text = r[key] or "",
-            } or r[key]
-        end
-    end
-
-    while true do
-        local items = {}
-        for k, v in pairs(vars) do
-            table.insert(items, {title = string.format("%s = %s", k, tostring(r[k])), result = k, align = -1})
-        end
-        table.insert(items, {title = "Done", result = "DONE", align = 0})
-
-        local action = choice{
-            title = title,
-            items = items,
-        }
-        if action == "DONE" then
-            break
-        else
-            r[action] = ask_value(action)
-        end
-    end
-
-    return r
-end
-
-return t
\ No newline at end of file
diff --git a/apps/formsolver.lua b/apps/formsolver.lua
deleted file mode 100644
index cb53a85..0000000
--- a/apps/formsolver.lua
+++ /dev/null
@@ -1,126 +0,0 @@
-local m = {}
-
-local function formula_get_vars(str)
-   local res = {}
-   for v in str:gmatch('%{%w+%}') do
-      table.insert(res, v:sub(2, -2))
-   end
-   return res
-end
-
-local function formula_replace_vars(str, tab)
-   return str and str:gsub('%{%w+%}', function(key)
-      key = key:sub(2, -2)
-      return tab[key] and '(' .. tab[key] .. ')' or key
-   end)
-end
-
--- Mask variables for symbolic solve/isolation
-local function formula_mask_vars(str)
-   return str and str:gsub('%{%w+%}', function(key)
-      return '(m_' .. key:sub(2, -2) .. '_m)'
-   end)
-end
-
--- Unmask masked variables
-local function formula_unmask_vars(str)
-   return str and str:gsub('m_%w+_m', function(key)
-      return key:sub(3, -3)
-   end)
-end
-
-local function build_formula_solve_queue(want_var, set, formulas)
-   local var_to_formula = {}
-
-   if type(want_var) == 'string' then
-      want_var = { want_var }
-   end
-
-   -- Insert all given arguments as pseudo formulas
-   for name, value in pairs(set) do
-      var_to_formula[name] = name.."=("..value..")"
-   end
-
-   -- Returns a variable name the formula is solvable for
-   -- with the current set of known variables
-   local function get_solvable_for(formula)
-      local missing = nil
-      for _, v in ipairs(formula_get_vars(formula)) do
-         if not var_to_formula[v] then
-            if missing then
-               return nil
-            end
-            missing = v
-         end
-      end
-      return missing
-   end
-
-   for _ = 1, 50 do -- Artificial search limit
-      local found = false
-      for _, v in ipairs(formulas) do
-         local var = get_solvable_for(v)
-         if var then
-            var_to_formula[var] = v
-            found = true
-         end
-      end
-      if not found then
-         break
-      end
-   end
-
-   -- Build list of formulas that need to be solved
-   ---@type string[][]
-   local solve_queue = {}
-
-   local function add_formula_to_queue(formula, solve_for)
-      if not formula then return end
-
-      -- Remove prev element
-      for i, v in ipairs(solve_queue) do
-         if v[1] == solve_for and v[2] == formula then
-            table.remove(solve_queue, i)
-            break
-         end
-      end
-
-      -- Insert at top
-      table.insert(solve_queue, 1, { solve_for, formula })
-
-      for _, v in ipairs(formula_get_vars(formula)) do
-         if v ~= solve_for then
-            add_formula_to_queue(var_to_formula[v], v)
-         end
-      end
-   end
-
-   for _, v in ipairs(want_var) do
-      print('info: adding wanted var ' .. v .. ' to queue')
-      add_formula_to_queue(var_to_formula[v], v)
-   end
-
-   return solve_queue
-end
-
-function m.solve_for(var, set, formulas, fn)
-   fn = fn or 'nsolve'
-   local q = build_formula_solve_queue(var, set, formulas)
-   local steps = {}
-   for _, v in ipairs(q) do
-      local variable, formula = v[1], v[2]
-
-      -- Solve numeric
-      local numeric = math.evalStr(string.format('%s(%s,%s)', fn, formula_replace_vars(formula, set), variable))
-      set[variable] = numeric
-
-      -- Solve symbolic (for steps)
-      local symbolic = formula_replace_vars(formula, {})
-      if symbolic then
-         table.insert(steps, { formula = symbolic, var = variable })
-      end
-   end
-   return set, steps
-end
-
-return m
diff --git a/apps/init.lua b/apps/init.lua
index 1b0bfc3..b5f79c2 100644
--- a/apps/init.lua
+++ b/apps/init.lua
@@ -1,10 +1,3 @@
 require 'apps.apps'
---require 'apps.app_formulas'
-require 'apps.app_trassierung'
-require 'apps.app_punktsteigung'
-require 'apps.app_triangle'
 require 'apps.app_constants'
-require 'apps.app_binom'
---require 'apps.app_analyze_fn'
-
-require 'apps.AnaGeo'
\ No newline at end of file
+require 'apps.AnaGeo'