The “easy”, “medium”, and “hard” scale of exercise difficulty is not conducive to trial, error, exploration, and challenge. There are a number of problems:
Chilis are an alternate scale for exercises. The scale is not absolute - any number of chilis can be added to an exercise, and it is not used to denote difficulty as much as “spice”.
The chili scale was used at Canada/USA Mathcamp both when I was a camper and a counselor. The execution and result was excellent, so I decided to use this system myself. The idea was to denote a scale that talks about the challenge of a problem rather than a difficulty level. It helps with encouragement, the ability to scale exercises, and a sense of adventure necessary in all difficult pursuits. Oh, and the metaphor is fantastic. It’s not quite the firehose, but it’s the next best thing.
Enjoy the chili system - take as much spice as you can get!