Isometric projection began as a mechanical drawing standard at Cambridge University in 19th-century England — proposed by William Farish in 1822 so that every dimension on an engineering blueprint could be measured directly, without perspective distortion. For over a hundred years it lived only in engineering classrooms.

In 1982 the games industry discovered it: Q*bert used isometric projection to build a 'pyramid' feel; in 1989 SimCity used it to draw an entire city; later Diablo, Age of Empires and Civilization — all thanks to that 30-degree line — made 2D 'look like 3D' without ever computing real 3D.

From 2014, SaaS companies fell in love with it: the website illustrations of Slack, Mailchimp and Dropbox all use the isometric style — because it is cute, unintimidating, and can pack in plenty of detail, while being far cheaper than real 3D. In the 2010s the indie game Monument Valley fused it with M. C. Escher's optical illusions — becoming one of the most beautiful works in mobile-game history.

The trap: it's too charming, too 'brand illustration.' When every startup uses it, the whole SaaS industry starts to look the same. Today the smarter approach is 'isometric + a touch of perspective / varied thickness / real lighting' — keep the structure, add the personality back.