Float xa[10][51], ya[10][51], za[10][51]
Float xb[51], yb[51], zb[51]
Float xxa[10][51], yya[10][51]
Float xxb[51], yyb[51]
Float sia[10], coa[10]
Float dxa[10], dya[10]
Int cnta[10],x[10],y[10]
Int c[3]
Randomize
num = 3
c[0] = 7; c[1] = 6; c[2] = 4
sia[0] = .2
coa[0] = Sqrt(1 - sia[0] * sia[0])
sib = .7
cob = Sqrt(1 - sib * sib)
Do k = 1 To num
   sia[k] = rand()/2-0.25
   coa[k] = Sqrt(1 - sia[k] * sia[k])
Loop
n = 50
a = .0025
s = 7
Do j = 0 To num
   x[j] = 320; y[j] = 240
Loop
Do k = 1 To 50
   Do j = 0 To num
      xa[j][k] = x[j]; ya[j][k] = y[j]
   Loop j
   xb[k] = 320; yb[k] = 240
Loop k
Do k = 1 To 50
   za[0][k] = c[k%3] + 8
   zb[k] = c[k%3]
   Do j= 1 To num
      za[j][k] = 2+Random(2)+8*Random(2)
   Loop j
   za[0][3] = 15; za[1][3] = 15
Loop k
Do j= 0 To num
   dxa[j] = 0; dya[j] = 0
   cnta[j] = 15
Loop
cntb = 9
Do
   Read quit key (27)
   Do k = 1 To n
      xxb[k] = xb[k]; yyb[k] = yb[k]
      Do j = 0 To num
         xxa[j][k] = xa[j][k]; yya[j][k] = ya[j][k]
      Loop j
   Loop k
   Do j = 0 To num
      dxa[j] = dxa[j] + .5 * s * (rand() - .5) + a * (320 - xa[j][1])
      dya[j] = dya[j] + .5 * s * (rand() - .5) + a * (240 - ya[j][1])
      r = Sqrt(dxa[j] * dxa[j] + dya[j] * dya[j]) + 1
      dxa[j] = s * dxa[j] / r; dya[j] = s * dya[j] / r
      dxatmp = dxa[j] * coa[j] + dya[j] * sia[j]
      dya[j] = dya[j] * coa[j] - dxa[j] * sia[j]
      dxa[j] = dxatmp
      xa[j][1] = xa[j][1] + dxa[j]; ya[j][1] = ya[j][1] + dya[j]
   Loop j
   dxb = xa[0][1] - xb[1]; dyb = ya[0][1] - yb[1]
   r = Sqrt(dxb * dxb + dyb * dyb) + 1
   dxb = .5 * s * dxb / r; dyb = .5 * s * dyb / r
   dxbtmp = dxb * cob + dyb * sib
   dyb = dyb * cob - dxb * sib
   dxb = dxbtmp
   xb[1] = xb[1] + dxb; yb[1] = yb[1] + dyb
   Do k = 2 To n
      xb[k] = (3*xb[k - 1] + 2*xb[k]) / 5
      yb[k] = (3*yb[k - 1] + 2*yb[k]) / 5
      Do j = 0 To num
         xa[j][k] = (3*xa[j][k - 1] + 2*xa[j][k]) / 5
         ya[j][k] = (3*ya[j][k - 1] + 2*ya[j][k]) / 5
      Loop j
   Loop k
   cntb = cntb - 1
   If cntb = 0 
      sib = -sib; cntb = Int(6 * rand() + 6)
   End If
   Do j = 0 To num
      cnta[j] = cnta[j] - 1
      If cnta[j] = 0 
         sia[j] = -sia[j]; cnta[j] = 15
      End If
   Loop j
   Delay (25); Cls
   liner (n - 23, xb, yb, zb, 3) @
   Do j = 0 To num
      liner (n, xa[j], ya[j], za[j], 5) @
   Loop
Loop

//---------------------------------------------------------------------------

Task liner (Int n, Float x[], Float y[], Float z[], Int rad)
   r = Float(rad)
   s = 2
   Do k = s To n - 1
      Solid color (z[k+1])
      Solid circle (x[k+1], y[k+1], r)
      r = 0.98*r
   Loop k
End liner

//---------------------------------------------------------------------------

Float rand()
   Return Random(25000)/25000.0
End rand