Energy is never created or destroyed.
The first law of thermodynamics
Everything in fisika rests on one sentence: energy is never created or destroyed. It is the first law of thermodynamics, it is the name on our door, and it has turned out to be the most useful design rule we have.
Fire is where you see it first.
A tree is a savings account
A tree in fisika does not contain heat. It contains stored sunlight, and fire is the transaction that spends it. When a log burns out, the fire has not got bored. The log has run out of savings.
Every material in the world can say four things about itself: how fast it warms up next to something hot, how stubbornly it holds its temperature, how long it burns before it is spent, and what it turns into. Wood becomes fire becomes ash. Water becomes steam.
Fire never creates energy. It spends savings.
Nothing here is an effect
None of this is painted on top of the world. Heat moves from voxel to voxel, slowly through stone, and whatever will catch, catches. Grass burns outward from a fireball because the grass beside it got hot enough, and the fire stops where there is nothing left to spend.
The same law binds magic
The player is bound by it too. A ring does not conjure fire out of nothing: it draws heat, light or motion from the world around it, and the world shows the bill in frost, shade, withered crops or still air. That is the whole of fisika's magic, and it is the subject of the next post.
