The hearts of the Super Nintendo
Every computer has at least one heart which beats the cadence to all the other chips. The CloCK output pin is connected to a copper line which spreads to most components, into their CLK input pin.
If you are mostly a software person like me, you may have never noticed it but all kinds of processors have a CLK input pin. From CPUs (Motorola 68000, Intel Pentium, MOS 6502), to custom graphic chips (Midway's DMA2, Capcom CPS-A/CPS-B, Sega's Genesis VDP) to audio chips (Yamaha 2151, OKI msm6295), they all have one.
Fabien Sanglard
I've watched enough Adrian Black that I already knew all of this, and I'm assuming so did many of you. But hey, I'll never pass up the opportunity to link to the insides of the Super Nintendo.