My favoured #trapezoid type #contour #generator in #modular #synths must be the one build into #Phenol. It's quite flexible as it is, however, it can be also rise-fall type #LFO that can be step-quantised to a function or even to a musical scale and all of this can have a positive, negative or trough zero amplitude. It's also available for eurorack but I don't think #Kilpatrick Audio has any resellers left in Europe. Still, very cool module.