PUZZLE #4216: Prism Refraction Cipher [prism: triangle] (diff 2)

prism-refraction learn difficulty: 2/7 compute author: system unsolved

Laser through a triangle prism. 4 shots = 4-char word.

DATA

Difficulty	`2`
Columns	`4`
Wall	{ "shape": "circle", "radius": 15.0, "center": [ 0.0, 0.0 ] }
Prism	{ "shape": "triangle", "center": [ 3.0, 0.0 ], "rotation": -0.0578, "params": { "side": 3.0 }, "refractive_index": 1.607 }
N Chars	`26`
Shots	`{'laser_angle_deg': 0, 'exit_angle': 4.119453}, {'laser_angle_deg': 0, 'exit_angle': 4.119453}, {'laser_angle_deg': 0, 'exit_angle': 4.119453}, {'laser_angle_deg': 0, 'exit_angle': 4.119453}`
Hints	`Prism Refraction: 4 shots, prism=triangle, wall=circle, n=1.607`
Hint	`Prism Refraction Cipher (diff 2). Wall: circle, prism: triangle at (3.00,0.00), n=1.607. 4 laser shots, one per character. Trace each laser through the prism using Snell's law. The exit ray hits the wall at a character. Read them in order. Submit the 4-character word.`
Answer Format	`lowercase decoded message`

{
  "type": "prism-refraction",
  "difficulty": 2,
  "columns": 4,
  "wall": {
    "shape": "circle",
    "radius": 15.0,
    "center": [
      0.0,
      0.0
    ]
  },
  "prism": {
    "shape": "triangle",
    "center": [
      3.0,
      0.0
    ],
    "rotation": -0.0578,
    "params": {
      "side": 3.0
    },
    "refractive_index": 1.607
  },
  "n_chars": 26,
  "shots": [
    {
      "laser_angle_deg": 0,
      "exit_angle": 4.119453
    },
    {
      "laser_angle_deg": 0,
      "exit_angle": 4.119453
    },
    {
      "laser_angle_deg": 0,
      "exit_angle": 4.119453
    },
    {
      "laser_angle_deg": 0,
      "exit_angle": 4.119453
    }
  ],
  "hints": "Prism Refraction: 4 shots, prism=triangle, wall=circle, n=1.607",
  "hint": "Prism Refraction Cipher (diff 2). Wall: circle, prism: triangle at (3.00,0.00), n=1.607. 4 laser shots, one per character. Trace each laser through the prism using Snell's law. The exit ray hits the wall at a character. Read them in order. Submit the 4-character word.",
  "answer_format": "lowercase decoded message"
}

author's note: Pool fill: prism-refraction diff 2