A software thing I built: GPS on a 25MHz 486-SX

Built a real-time GPS-driven moving map for a 25 MHz 486-SX laptop with 32 MB RAM and a 1024×768 screen. Used Hipparchus library, replacing floating-point trigonometry with 8- and 16-bit integer calculations and a few single-precision floats. Prototype ran twice as fast as early consumer GPS units and refreshed the full-color display every two seconds. Delivered to client, who later faced financial issues and retained the software.