{	2 { 1 add 2 div 3 mul dup floor sub 2 mul 1 sub exch } repeat
	dup mul exch dup mul add 1.0 exch sub } 

{2 mul abs exch dup mul add 3 div 2 mul 1 exch sub} 

{abs exch abs 2 copy gt{exch}if pop} 

{dup mul exch dup mul add 1.0 exch sub} 

currentscreen 
dup type (dicttype) eq 
{/SpotFunction get} if
3 1 roll pop pop