What is a Low Feature Count Challenge?
It is generally "simple" looking model, but we try to solve it in as few operations as possible. Anyone could build these "simple" models in 5 - 10 features, but have you tried to solve them with only 1 - 3 features? It takes some skill, and critical thinking to solve these challenges.
These challenges are less challenging once a solution or hint is found, so let's keep the solutions in a separate discussion. People looking for the answer can find it, but those who enjoy the challenge of solving a puzzle will be safe from spoilers.