Round & Revel / Reversible switch puzzle
Lights at Closing
The helpful switch turns something else back on.
Original authored print-and-play game. Time is a planning estimate; this edition has not had a live group playtest.
Good for: A quiet table that likes testing a small idea and following its consequences.
What you need
- One seven-lamp board and seven paper markers; a marked lamp is ON
- One public seven-switch reference and eight challenge cards, plus practice LC00
- Pencil, move log, and separate covered answer guide
How to play
Close the lamps together
Your group controls seven numbered lamps with seven lettered switches. A switch flips every lamp listed beside it: ON becomes OFF and OFF becomes ON. Other lamps stay as they are. The challenge is to reach the complete target pattern using no more than the printed PAR number of presses. There are no hidden facts, keeper roles, or real electrical components. Everyone can read the switches and help plan.
Prepare the panel
Print one board and one switch reference. Make seven markers from scrap paper and number them 1–7. Put a marker in its matching board box when that lamp is ON; keep it just below the box when OFF. Never use a marker in another lamp’s box. Write a move log with a line for each press. Keep the answer guide covered and set LC00 aside for practice.
Choose the evening’s work
Choose three different challenges LC01–LC08 without reading their keys. Play them in any agreed order, using a fresh log each time. At the start of a challenge, clear the board and turn ON exactly the lamps in START. Every other lamp is OFF. The TARGET lists every lamp that must be ON at the finish; lamps not listed there must be OFF. NONE means no lamps.
Understand a reversible press
Pressing a switch means flipping all its listed lamps once as one complete action. You may use any switch again, including the one just used. Two presses of the same switch cancel each other, but both still count. Switch order never changes the final result of a chosen set of presses. You still need to find the right set; turning on a desired lamp can accidentally turn another desired lamp off.
Give everyone a turn
Choose a first operator and continue clockwise, keeping the rotation between challenges. Before pressing, the operator proposes a switch or says “thinking pass.” Anyone may ask a question, offer a different plan, or point to a consequence. The operator makes the final choice after hearing the table. A pass does not change the board or use a press. After a press, the next player checks the listed lamps and writes the switch letter in the log.
Plan freely, commit clearly
You may draw candidate patterns, count effects, and discuss an entire solution before moving anything. Planning marks on scrap paper are free. Say “press A,” for example, before changing the actual panel. Once the complete press has been applied correctly, it counts and cannot be erased from the log. You can reverse it with another paid press. This distinction allows careful planning without turning accidental handling into a penalty.
Check the whole panel
After each press, compare all seven lamps with TARGET. Stop immediately when the whole pattern matches and write the number of presses. A partially correct panel never counts as a finished puzzle. The maximum attempt is PAR plus two presses. If that last press does not finish, stop and open the key. You may also end an attempt early by agreement; do not use the answer and resume for points.
Score and move on
Earn 2 shared points for reaching TARGET within PAR, 1 for reaching it within PAR plus two, and 0 otherwise. Practice does not score. After three challenges, add the points for a total out of 6; there are no individual winners or tiebreakers. Every shortest solution is valid, including a different ordering of the same switches. The guide gives one solution and the checked minimum, rather than a required performance to copy.
Repair handling errors and make space
If a press was applied incorrectly, use the log and previous pattern to fix its effects before the next turn; the intended press still counts once. If the state cannot be recovered, reset that challenge and play it unscored. Large boxes, an aloud reader, and a helper moving exactly the named markers are welcome. Remove any time pressure. On replay, use unseen challenge cards or attempt a known card as an unscored explanation exercise.
A worked example
Use practice LC00. Set START to 4, 6. Press D then F. Flip every lamp listed for each press, including any lamp affected twice. The final ON lamps are 1, 2, 3, 4. This uses 2 presses, exactly PAR, so it would earn 2 points on a scored card. Applying either switch a second time would undo its effects and still cost a press.
Printable materials
Print one copy of the panel, switch reference, and cards single-sided. Keep the public switch reference visible. Cut challenge cards if convenient; make seven numbered scrap-paper markers. Print the answer guide separately and cover it until an attempt ends.
Seven-lamp panel
A marker in a box means ON. No marker means OFF. Keep each numbered marker below its own box when OFF.
On a small screen, scroll this table sideways.
| Lamp 1 | Lamp 2 | Lamp 3 | Lamp 4 | Lamp 5 | Lamp 6 | Lamp 7 |
|---|---|---|---|---|---|---|
| ON / OFF | ON / OFF | ON / OFF | ON / OFF | ON / OFF | ON / OFF | ON / OFF |
Public switch reference
| Switch | Flip these lamps |
|---|---|
| A | 6, 7 |
| B | 2, 4, 6 |
| C | 2, 3, 5 |
| D | 2, 6 |
| E | 3, 6 |
| F | 1, 3 |
| G | 4, 6 |
Practice panel
START ON: 4, 6
TARGET ON: 1, 2, 3, 4
PAR: 2 presses. Maximum attempt: 4 presses.
Closing panel 1
START ON: 2, 5, 6, 7
TARGET ON: 1, 3, 5, 6, 7
PAR: 3 presses. Maximum attempt: 5 presses.
Closing panel 2
START ON: 1, 2, 4, 5, 6, 7
TARGET ON: 3, 4, 5, 6, 7
PAR: 3 presses. Maximum attempt: 5 presses.
Closing panel 3
START ON: 1, 2, 6
TARGET ON: 2, 3, 5, 6
PAR: 4 presses. Maximum attempt: 6 presses.
Closing panel 4
START ON: 1, 4, 6, 7
TARGET ON: 1, 4, 5, 7
PAR: 4 presses. Maximum attempt: 6 presses.
Closing panel 5
START ON: 1, 2, 3, 4, 5, 7
TARGET ON: 1, 2, 3, 6, 7
PAR: 4 presses. Maximum attempt: 6 presses.
Closing panel 6
START ON: 2, 4
TARGET ON: 1, 4, 5, 6
PAR: 5 presses. Maximum attempt: 7 presses.
Closing panel 7
START ON: 1, 6
TARGET ON: 1, 3, 7
PAR: 5 presses. Maximum attempt: 7 presses.
Closing panel 8
START ON: 4, 5
TARGET ON: 1, 4, 6, 7
PAR: 5 presses. Maximum attempt: 7 presses.
Host material: Open the separate Lights at Closing answer notes. Contains solutions. Keep this guide away from players.
Round & Revel. First edition, October 2026. Uses only the listed printable materials and ordinary supplies.