What it moulded
Draft copy · to be checked against sources
Before the red disc, a timer gave you a number. Numbers have to be read, then subtracted from something, then felt. This one skips two of those steps. It shows time as an amount: a slice of red that is visibly smaller than it was a moment ago.
A deadline stopped being a moment that arrives, and became a quantity you spend.
It asks nothing of you but a glance. The disc does the arithmetic, which is why it turns up wherever people need to feel time passing rather than calculate it.
The habit it moulded is a small and useful one: looking at time the way you look at a glass of water, and knowing, without counting, how much is left.