We also see the moon-phase at twelve, and the continued use of a peripheral date display. Sales of these three models would begin in 1959. While certainly a complicated way of showing the leap year, this was
link the first time it had been done by any brand in series production, and you don't have
link to look all that closely to see these later 5516s as something of
link an aesthetic and philosophical foundation upon which AP has built much of its modern success.