//nothing lasts forever
//not even time
//the program selfdistructs in due time.
paper 50
forever

{

set lone (lone+1)
set ltwo (ltwo +2)
set lthree (lthree-3)
set lfour (lfour +4)
notsmaller? lone ([53 50]+[48 49])
{
set lone 0
}
notsmaller? ltwo ([50 50]+80)
{
set ltwo 0
}
notsmaller? lthree ([51 51]-[50 49])
{
set lthree 0
}
pen lone
line [22 9] [8 5] lone ltwo
pen ltwo
line [12 19] [2 21] lthree ltwo
pen lthree
line [52 50] [42 50] ltwo lthree
}

//this is a modification of mas961 akilian problem set.