Cody Tumblin, a design student from Chicago, Illinois, USA, made a series of monochrome calendars.

The calendars come in three different colors: red(s), blue(s), and black(s). Each color-way has a delicate shift between the values of each color so that the calendar slightly vibrates visually. Tumblin describes them as:

An exploration of subtle monochromatic palettes that really explode in color.

Each number on the calendar is hand-drawn so each calendar is unique. Wow!