Feedforward loops (FFLs) are the most abundant 3-node motif in gene regulatory networks (Milo et al. 2002, Science). X→Y→Z and X→Z. The C1-FFL (coherent type 1, both paths activate) acts as a sign-sensitive delay and pulse filter — it ignores brief input fluctuations. The I1-FFL (incoherent: X activates Z but X→Y inhibits Z) generates pulse acceleration and adaptation.