I Squared Equals 1 Hats

Description: A stark black background features a mathematical equation in white text. The equation reads 'i² = -1'. Below this, another line of text states 'The origin of complex numbers'. The overall presentation is minimalist and educational.

Description: A white mathematical equation on a black background. It shows the square root of negative one, followed by a fraction with Delta 1 squared over 2 squared, and an equals sign leading to Pi.

Description: A great design for coffee loving scientists! Design reads E=coffee² and features an atom with three coffee bean in orbit.