Richard Walker - 2022-12-01

A work around is to use a voltage source and then convert it to a current source with a G device:

vinput 101 0 PWL(0 0 {PER/4} {STROKE} {2PER/4} 0 {3PER/4} {-STROKE} {PER} 0) R=0
ginput 1 0 101 0 1