You probably know the noun and verb meanings of arch, so we'll go with the adjective version. As an adjective, it means chief/primary or mischievious and teasing, often in a forced, ironic playfulness.
PencilsMachinesUseless thingsCool thingsPerfect loopsThe creative process
In the Soviet Union, people smuggled banned Western music into the country by printing it on x-rays (vinyl was hard to come by). This is a really crazy, cool story. Necessity is the mother of invention, I guess.
MusicScienceIngenuityBack in the U.S.S.R.