Fellow ChucKists, This is runs; <<<-1 * second>>>; Hence we know that negative durations are fine. This, on the other hand causes a problem; <<<-1::second>>>; We can get around that by using this; <<<(-1)::second>>>; That one does run but it also seems very clumsy to me. I'm getting the impression that for durations expressed like -3::second the minus sign somehow isn't a part of the number while elsewhere it is. This doesn't strike me as very coherent. While I was testing some other things around negative durations I noticed that this will crash with seg-fault; second -=> now; Admittedly it would be a type of expression that would only be useful with negative durations... Probably quite rare but it shouldn't crash the whole VM like that. Yours, Kas.