Four sound samples: one tube or four copies

Four input samples, one tube and four copies with their outputs The input sound has four samples, x0 to x3. One tube receives one sample per step. Four equally sized copies each receive their own sample on the first step and all step together. Triangles point toward the lips or back toward the glottis; colour identifies the input sample and area shows strength on one fixed scale. Each tube uses the shape of the time it simulates, printed under its label. Beside every tube, signed stems show its output on the same time axis as the input. Each copy starts at its sample's time. The copies need only the steps to cross the tube and let the echo fade, 15, however many samples there are; the one tube also needs a step per sample, 18 in total. When the copies finish, their sum is compared with the one tube's output. The largest difference is less than 0.001. Step zero is before any step.