Seven-Segment Logic

Owner:

Andy

Solution:

DEBUGGER

GC Notes:

GC to update day-of-game.

Presentation:

Teams receive an envelope containing a series of circuit-diagram looking pages; two (duplicate) sheets are labelled "sample circuits" and then four sheets that are the actual puzzle.

Walkthrough:

Looking at the sample circuits first, teams should be able to determine what the three logic gates do; the red gate with the "radioactive" symbol is a NOT gate, the blue gate with a "mac command" symbol is an AND gate, and the green gate with a "recycle" symbol is an OR gate. The three gates operate on an input of seven-segment displays as follows. (Note: the example circuits below are in most cases simpler than the circuits on the sample sheet provided to teams, who will need to do just a bit of inference to determine what these gates do.)

NOT gates: this toggles each segment on the input:

AND gates: only segments which are lit on both inputs are lit on the output:

OR gates: segments which are lit on any input are lit on the output:

The overview diagram shows three components (labelled A, B, and C) and there are three unlabeled diagrams of these components, but they can be differentiated because each component has a distinct combination of inputs and outputs.

Other than these insights; the rest of the puzzle is just rote tracing the circuits and manually performing the logic operations to get the output, which will be the word DEBUGGER, written in displays. It should look like the following:

Most letters are recognizable; teams may have some issues with the G (which is uppercase and looks like a 6) and the R (which is drawn in lowercase).

Hinting:

Not really any obvious ways to hint this; it's mostly about double-checking work and not making mistakes. If they can't read the letters, cluing them as to whether they're looking at an upper or lowercase letter might help.