Embed Notice

REM Based on an Akiyoshi Kitaoka illusion - "Red Cushion"
MODE0
VDU19,0,7;0;19,1,1;0;5
DIMl(511)
FORx=0TO511
t=x/511
l(x)=ACS(t*2-1)/3.14
NEXT
FORx=0TO511
FORy=0TO255
u=l(x)*15
v=l(y+y)*15
P=INTu
Q=INTv
p=u-P
q=v-Q
c=0
IF((P+Q)AND1)=0c=1-c
sx=p-.5
sy=q-.5
cx=ABS(ABSsx-.3)
cy=ABS(ABSsy-.3)
IFx<256 sx=-sx
IFy<128 sy=-sy
IF(SGN(sx)<>SGN(sy)OR(P=7ANDQ=7))IF(cx<.14ANDcy<.14)c=1-c
GCOL0,c
PLOT69,128+x*2,y*4
NEXT,
REPEATUNTIL0
REM #BBCMicroBot 🚀