"shadow_art.p8" created for @sableRaph's #WCCChallenge

shadow_art.p8

pico-8 cartridge // http://www.pico-8.com
version 38
__lua__
_set_fps(60)
-- enable use of second onscreen palette
poke(▒|▤,웃/●)
r=rnd
s=r(-1)
srand(s)
function reset()
cls()
g=r(5)-3
a=r(5)-3
b=a/3
z=r({2,3,4})
w=r({1,3})
c=r(3)+2
while(g+a)%b==g do a=r(5)end
end
reset()
col_offset = 0
-- define the palettes
pal({[0]=12,140,1,129,14,8,2,3,11,141,7,10,6,8,141,140},1,4)
pal({[0]=140,1,129,130,2,136,130,132,131,139,130,0,138,5,136,130,129},2)
cls()::_::
-- entropy locking
if(r()>.6)srand(s)
for x=g,130,z do for y=g,130,w do
circ(x,y,r(2),(x*y%c)+col_offset)end end
-- activate second palette
memset(0x5f78,0xfff,8)
-- set right side of screen to second palette
poke(0x5f2c,132) 
-- every 2 seconds, change the palette
if(t()%1==0)then
 col_offset += 1
 if(r()>.8 or t()%5==0)s+=1reset()
end
flip()
goto _