a   = P 0 50
bb  = P 0 50.5
ccc =+ a bb
d   = P 1 2 6.4
ee  = + d a
fff = * d d
g   = * fff fff
h   = * g fff
i   = - h
i   =-i
j   = + h d
h P
h   = P 0 20
h P
i   = P 2 3 2 1
j   = * i i
k   = + j d
k   = + k k
orange = + grape grape
apple = * k pear
grape = - apple
orange P
quit