Sofa

IKEA founder Ingvar Kamprad had dyslexia. To make product codes easier for him to handle, IKEA uses memorable names instead of numbers. Sofas take Swedish place names, while beds and wardrobes take Norwegian place names.

The 'Moving Sofa Problem'—finding the largest shape that fits around a right-angled hallway of width 1—was an unsolved mathematics conjecture for 60 years. In 2024, Korean mathematician Jineon Baek proved the 'Gerver sofa' (area ~2.2195) is optimal without computers.