On the Subject of Warning Signs

It’s much easier to not screw up if you haven’t screwed up already.

DANGER! This module shows a large sign to warn you about a specific hazard. To disarm the module, detach the sign by unscrewing its screws, one at a time, when the last seconds digit of the countdown timer is a valid digit.

Get three valid timer digits by following these steps:

1. Construct a triangle as shown in the diagram by filling in the digits 0 to 9. Start with the first digit of the serial number at the top and continue in reading order, increasing each subsequent digit by 1. Wrap back to 0 if you exceed 9.
2. Receive a number from Table SGN by using the hazard shown on the sign and the correct column following these rules:
   • If the number of unsolved* modules is a multiple of 4 use column D.
   • Otherwise, if the number of unsolved* modules is a multiple of 3 use column A.
   • Otherwise, if the number of unsolved* modules is a multiple of 2 use column N.
   • Otherwise, use column G.

   * this includes needy modules.

3. In the triangle, find all possible equilateral triangles in which the received number appears in a corner position. Then, locate the three numbers that don’t appear in corner positions of these triangles.

Unscrewing a screw is valid if the last seconds digit of the countdown timer matches one of these three numbers.

NOTE: Make sure to unscrew one screw for every valid timer digit. Moreover, the whole process cannot exceed 9 timer ticks from the first unscrew. Taking too long or unscrewing on an invalid timer digit will result in a strike.

Table SGN: Warning Sign Reference

Hazards1	D	A	N	G
General warning <!>	1	8	3	7
Flammable material <flames>	6	7	2	8
Radioactive material <three segments of a circle around a dot>	3	0	7	6
Toxic material <skull>	7	2	5	3
High temperature <thermometer>	9	5	4	0
Low temperature <snowflake>	2	5	3	4
Mind your head <person bumping their head>	3	4	9	5
High voltage <lightning bolt>	0	1	9	7
Irritant <X>	7	8	1	3
Explosive substance <bursting object with speed lines>	6	4	7	2
Biohazard <three crescent moons joined at the center on top of a circle>	6	8	1	5
Laser beam <circle emitting rays>	2	7	4	0
Hazardous to the environment <dead tree and fish bones>	0	2	3	6
Corrosive substance <liquid dripping on a hand and a surface>	8	6	9	2
Rotating parts <hand in gears>	0	4	8	5
Deep water <person above water line>	1	4	0	8
Risk of falling <person falling>	9	1	5	6
Cameras <surveillance camera>	1	5	9	4
Falling objects <falling brick, wrench and hammer>	8	9	2	3
Slippery floor <person slipping>	8	6	1	9

¹ The text inside the angle brackets is a description of the sign’s iconography.