The Bookmark and the Whiteboard

Imagine you're reading a recipe book while cooking. You use a bookmark to keep track of which step you're on (that's the Program Counter - always pointing to the next instruction). Meanwhile, you write calculation results on a whiteboard next to you (that's the Accumulator - storing intermediate results). Just as you move the bookmark down one step after reading each instruction, the PC increments after each fetch. And just as you erase and rewrite on the whiteboard with each new calculation, the ACC updates with each ALU operation.