png 120 120 hw1trica.png

xyc 10 10    #000000
xyc 10 100   #000000
xyc 100 10   #000000
xyc 100 100  #000000

trica 1 2 3 #ff0000ff
trica 1 2 4 #00ff007f
trica 2 3 4 #0000ff3f
trica 1 3 4 #ffffff28