using_your_c64_a.bas

10 print chr$(147)
20 ca = 1024: cp = 54272: r = 25: co = 40
30 poke 53280,0: poke 53281,0
40 for w = 3 to 50
50   for i = 1 to 12
60     for j = 0 to 12
70       k = i + j
80       c = j + j + j / (i + 3) + i * w / 12
90       k1 = ca + i + (co * k)
100      i1 = ca + k + (co * i)
110      c1 = cp + k1: c2 = cp + i1
120      k2 = ca + (co - i) + (co * (r - k))
130      i2 = ca + (co - j) + (co * (r - i))
140      c3 = cp + k2: c4 = cp + i2
150      k3 = ca + (co - i) + (co * k)
160      c5 = cp + k3
170      i3 = ca + k + (co * (r - i))
180      c6 = cp + i3
190      k4 = ca + (co - j) + (co * i)
200      c7 = cp + k4
210      i4 = ca + i + (co * (r - k))
220      c8 = cp + i4
230      poke k1,81: poke c1,c: poke i1,81: poke c2,c
240      poke k2,81: poke c3,c: poke i2,81: poke c4,c
250      poke k3,81: poke c5,c: poke i3,81: poke c6,c
260      poke k4,81: poke c7,c: poke i4,81: poke c8,c
270     next j
280   next i
290 next w
300 goto 10