What does puts [1, 2, 3].combination(2).to_a.inspect output?

Console output

Why

`Array#combination(n)` generates all combinations of `n` elements (order-independent). From `[1, 2, 3]`, the 2-element combinations are `[1, 2]`, `[1, 3]`, and `[2, 3]`. C(3,2) = 3 combinations.