Restructure again

main.typ

@@ -16,10 +16,11 @@
 #pagebreak()
 
 #chapter("src/frontmatter.typ")
+#chapter("src/sumcheck.typ")
+#chapter("src/pcp.typ")
 #chapter("src/ec.typ")
 #chapter("src/kzg.typ")
+#chapter("src/plonk.typ")
 #chapter("src/ipa.typ")
 #chapter("src/r1cs.typ")
 #chapter("src/mpc.typ")
-#chapter("src/sumcheck.typ")
-#chapter("src/pcp.typ")

src/pcp.typ

@@ -1,6 +1,14 @@
 #import "preamble.typ":*
 
-= A toy PCP protocol
+= The classical PCP protocol (optional)
+
+This entire chapter describes the first construction to PCP's.
+However, it's not used later on;
+so you can think of it as "really long example of sum-check application".
+But you can skip it in favor of the more modern protocols like zkSNARK's
+which are both better
+(according to metrics like message length or verifier complexity)
+and simpler (fewer moving parts).
 
 == Pitch: How to grade papers without reading them
 

src/plonk.typ

@@ -0,0 +1,11 @@
+#import "preamble.typ":*
+
+= PLONK, a zkSNARK protocol
+
+Earlier, we commented that the classical PCP construction was both
+more complicated and less practical than modern protocols.
+This chapter is going to present one such construction.
+
+== What is a zkSNARK anyway?
+
+TODO