Update

rock.md

@@ -7,12 +7,13 @@ Rocks are pretty [suckless](suckless.md) and [LRS](lrs.md) because they are simp
 - As a building material.
 - For [fun](fun.md) and entertainment, you can play various games with rocks: rock skipping, petanque, even [chess](chess.md).
 - As [weapons](weapon.md), even though we discourage this use.
-- For making tools such as [knives](knife.md).
-- To hold heat: you can e.g. heat stones in fire and let them heat you while you sleep.
+- For making tools such as [knives](knife.md) or [hammers](hammer.md).
+- To hold heat: you can e.g. heat stones in fire and let them heat you while you sleep or use them to cook something.
 - For writing, some can be used as a chalk, some may be used to carve text into. A dust from some rocks can be used to make dye to paint or write with.
 - As weights.
 - For help with counting (e.g. [abacus](abacus.md)) -- this makes rocks a kind of [computer](computer.md)!
 - To make [art](art.md), decorations, small statues etc.
 - For breaking things, grinding, sharpening etc.
 - With advanced technology we can get metals out of rocks, extract geological knowledge from them etc.
+- Some rocks can be used to start [fire](fire.md).
 - Some are pretty rare and can be used as a [currency](currency.md), even though we hate money and discourage this as well.