Three rows isolate packet energy as the source factor while packet count stays fixed. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Three ten-joule packets give thirty joules
Keep the packet count at 3. If each source packet carries 10 joules, the cycle receives 30 joules. This row changes packet size, not packet count.
3⋅10=30
Three twelve-joule packets match the earlier audit
With the same 3 packets at 12 joules each, total input rises to 36 joules. The diagram checks the larger energy arrow against the same three packet markers.
3⋅12=36
Three fifteen-joule packets make the packet-size slope clear
At 15 joules per packet, the fixed three-packet cycle has 45 joules of input. The three rows show that the total follows the source value directly.