Icon request for cold/warm/hot storage visualization

[ecircenis]

We need to visualize different classes of storage and having icons to represent the different classes would be useful. A flame for hot and a snowflake for cold seem to make sense, but "warm" is a tough one (coffee cup, thermos, mittens?). Another possibility is a thermometer (graphic, not icon) that could be placed next to metrics for the three storage classes.

[TimoTautenhahn]

Thanks for sharing those icons! How are they licensed? Can they be used in presentations publicly?