Fire! on pico8

m=32
f={}
h=25
s=1 --sub from ++++- field color
for i=1,130*h do
	--f[i]=m
	f[i]=0
end

--p={7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8}
p={
0,1,2,5,6, 
7,10,9,8,
9,10,7,
10,9,8,
13,11,15
}
p={
0,1,2,
8,9,8,9,10,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
}

function _init()
end


function _update()
	for y=2,h-2 do
		for x=2,126 do
			f[(y-1)*130+x] = 
			max(
			((
			f[y*130+x-1]+
			f[y*130+x]+
			f[y*130+x+1]+
			f[(y+1)*130+x]
			  )/4)-s,0)
			--if f[(y*130+1)+x] == nil then print "*" end
		end
	end
	--
	for y=h-3,h do
		for x=1,128 do
			--f[y*130+x]=rnd(m)
			f[y*130+x]=rnd(m)
			--f[y*130+x]=m
		end
	end
end

function _draw()
	cls()
	for y=0,h-7 do
		for x=1,128 do
			--col=f[y*130+x]
			
			ofs=flr((f[y*130+x]*#p)/m+1)
			pset(x,y+(128-h),p[ofs])

			--pset(x,y*2+(128-h)-h,p[ofs])
			--pset(x,y*2+(128-h)-1-h,p[ofs])
		end
	end
print(stat(1),10,10,1)

end

gistfile1.txt

fire is damn easy to burn:

- loop the screen in x and y from top/left to bottom/right.
- for each pixel do:
    get color/offset/... of pixels add them and divide by four and put the result one line above..
    
    like...    
    
         5
        123
         4    ...2 is your current x/y position... so calculate (1+2+3+4)/4 and put the result to 5.
         
 
 at the end put random colors all along the last line to keep it burning.
 
 
 
 FIRE! ;)