The full toy sequence forms the familiar rise-and-cut sawtooth shape.
highlighted = computed this step
The whole shape
Read the blue line left to right: fast rise, gentle rise, drop, then gentle rise again.
rise, rise, cut, rise
The pinned sequence
The cwnd values are 1, 2, 4, 8, 9, 10, 5, 6, 7, 8.
cwnd sequence is exact
After the cut, growth resumes
After the loss, the threshold is 5 and the next rows add one: 5, 6, 7, 8.
5→8
What this toy leaves out
This is a deterministic toy for reading cwnd dynamics. It is not measured throughput, latency, fairness, retransmission timing, or a full TCP implementation.
toy dynamics only
Summary
A sawtooth is the repeated pattern of increase and cut. Here every displayed row is recomputed from the pinned start, threshold, additive step, loss RTT, and row count.