Abaci are still widely used in the East, with slight variations in design--such as the number of beads and wires, and the presence of dividing beams--occurring between countries.

FORBES

Mr Black said the parliament's corporate body had not significantly altered requirements over the last four years and as such the main cause of the delay since September 2000 was the production of detailed variations in the design and the late delivery of information.

BBC: NEWS | UK | Scotland | Watchdog hits out over Holyrood

Other documents disclosed variations on the iPad design, including the fact the company considered a kickstand for the device.

WSJ: Apple's Secrets Revealed at Trial

"It's hard to understate the impact his ideas have had on the space, " says Phill Ryu, a developer who helped design the Clear task-management app, which uses variations on "pull-to-refresh" and has been downloaded more than 800, 000 times.

WSJ: Loren Brichter, a High Priest of App Design