If you have the newest Realistic City from dima-gord, SMKE is created in the open fire in the bottom right corner, this smoke travels up near the latter and ignites some wood, starting a fire in the hallway which spreads about.
lolzy but not all elements cause this, SMKE is a by product of fire and explosions, I can't boil oil now in an enclosed furnace without this happening.
I know.. If they added FOAM and LFOM that solidified when it got hot then you could use it to put out fires... Besides DIMA has already updated it. (well mine is at least)
The button in the bottom isn't really just heat as such, I thought it was legacy mode, so it would run the powder toy in the same style as the original (1 px lava pwns all!). Witch on a side note, switch seems to melt any conductor touching it with the heat sim turned off...