A logically equivalent transistor matrix is still used as the control store or microprogram or 'decode ROM' in many modern microprocessors.
The only activated control signals during that instant were those whose corresponding column wire was connected with a diode to that row.
A person would microprogram the control store on these computers by destroying the unwanted connections at selected intersections.
When reverse engineering integrated circuits that include such a mask-programmed decode ROM, one of the key steps is to take photographs of that ROM with enough resolution to separate each intersection site and enough color depth to distinguish between the "connected" and "not connected" intersections.
For a while the control store was many times faster than program memory, allowing a long, complicated sequence of steps through the control store per instruction fetch, leading to what is now called complex instruction set computing.