e = equal, l = left side down, r = right side down, → indicates marble is in that group but moves to the other side than it was previously
| Marble | weighings 1 | weighings 2 (opposite direction) | Groups that include the imposter |
|---|---|---|---|
| eee (not gonna happen) | |||
| A | eel | eer | 3 |
| B | ele | ere | 2 |
| C | ell | err | 2,3 |
| D | elr | erl | 2,→3 |
| E | lee | ree | 1 |
| F | lel | rer | 1,3 |
| G | ler | rel | 1,→3 |
| H | lle | rre | 1,2 |
| I | lll | rrr | 1,2,3 |
| J | llr | rrl | 1,2,→3 |
| K | lre | rle | 1,→2 |
| L | lrr | rll | 1,→2,3 |
With these groupings, you can use the end result to determine which marble is the impostor and whether it is heavier or lighter:
FGHL ▴ EIJK
BDHK ▴ CIJL
AFJL ▴ CDGI