M-Pesa Mobile Money is built from two things you would see in any Kenyan market town: a roadside duka painted top to bottom in Safaricom green, with M-PESA hand-lettered across it in white and red, and the numbered SIM Toolkit menu on a Nokia keypad phone that moves the money.

The system keeps both registers honest. Painted green walls, drifting brush baselines and a corrugated-iron band carry the brand; a narrow mono menu, four PIN boxes and a few plain receipt lines carry the transaction. Amounts are always the biggest thing on the page.