Perhaps the most cryptic table of factors ever published!
A remarkable table of trigonometrical functions.
An interesting example of Metapost reconstruction.
Construction of Soddy circles using Eppstein's algorithm.
An interesting example of a nomogram with which Easter can be found.
The oldest surviving key-driven adding machine.
Accurate drawings with style.
Were they also designed in a staircase?
Embodying the subtleties of twilight in 3D.
This machine uses no carries.
Walking the computus
Just follow the lines!
Designed in the 1840s for the manufacturing of precision gears.
18th-century tables based on Vlacq's tables.
16th-century sundials reconstructed with MetaPost.
A cycle of 532 years.
The oldest known of this kind.
The bell of the Mutte in Metz.
A new moon will be missing in 16399.
A few pieces in Oxford.
... in Science, not less than in War or Commerce, pertinacity of purpose is
one essential element of success. (George B. Airy)
Dr. Turing said it was really quite difficult to find useful things to do on a machine..., 1954