An age old wisdom - if you work manually, rest via mental efforts, and vice versa. For most HNers it means do tons of sweat inducing efforts, often, so mind can

An age old wisdom - if you work manually, rest via mental efforts, and vice versa. For most HNers it means do tons of sweat inducing efforts, often, so mind can rest a bit and do some defragmentation, not leaving everything only for sleep.