If a signal assignment is executed, and there are already old
transactions from a previous assignmenton the projected output waveform,
then some of the old transactions may be deleted. The way this is done
depends on whether the word transport is included in the new assignment.
If it is included, the assignment is said to use transport delay. In this case,
all old transactions scheduled to occur after the first new transaction are
deleted before the new transactions are added. It is as though the new
transactions supercede the old ones. So given the projected output
waveform shown immediately above, if the assignment: