ZXASCII
AUTO -1
PROG nets
10 paper 0: ink 15: cls: screen lock
20 FOR i=1 TO 31:
    FOR j=0 TO 7:
       f=1-(i/32),p=RGB j:
       PALETTE i*8+j,RED p*f,GREEN p*f,BLUE p*f:
    NEXT j:
 NEXT i
30 const x=1,y=2,c=3,r=4,dx=6,dy=7
40 def fn rdir=iif(rnd<.5, -1, 1)
50 nP=50,dt=130:
 dim p(nP,7),tri(3,3):
 for i=1 to nP:
    p(i,x)=rnd*scrw,
    p(i,y)=rnd*scrh,
    p(i,dx)=fn rdir*rnd*4,
    p(i,dy)=fn rdir*rnd*2.5,
    p(i,c)=1+int(rnd*7),
    p(i,r)=(rnd*2)+1:
 next i
60 cls:
 for i=1 to nP-2:
    for j=i+1 to nP-1:
       d=pyth(p(i,x)-p(j,x),p(i,y)-p(j,y)),
       m=8*INT(32*(d/dt)):
       if d<dt then
          tri(1,x)=p(i,x),tri(1,y)=p(i,y),tri(1,c)=p(i,c)+m,
          tri(2,x)=p(j,x),tri(2,y)=p(j,y),tri(2,c)=p(j,c)+m:
          for k=j+1 to nP:
             d1=pyth(p(k,x)-p(j,x),p(k,y)-p(j,y)),
             d2=pyth(p(k,x)-p(i,x),p(k,y)-p(i,y)):
             if d1<dt and d2<dt then
                tri(3,x)=p(k,x),tri(3,y)=p(k,y),tri(3,c)=p(k,c)+(8*int(32*(d/dt))):
                polygon ink p(i,c);tri():
             end if:
          next k:
       End if:
    next j
70  next i:
  plot p():
  for i=1 to np:
    p(i,dx)*=iif(p(i,x)<0 or p(i,x)>scrw,-1,1):
    p(i,dy)*=IIF(p(i,y)<0 or p(i,y)>scrh,-1,1):
  next i:
  particle p():
  wait screen
80 go to 60