A clock is an indexed event ledger with exact period spacing. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A clock edge ledger starts with one exact period
The period is 8 seconds, so each edge is spaced by that same amount.
T=8s
Changing period moves the same edge index
Each row keeps the selected edge fixed and recomputes its time from the period.
T4s6s8sn333tn12s18s24s
The edge index multiplies the period
Edge 3 is at 24 seconds because the period is repeated 3 times.