The idea in plain English: Imagine a square piece of land where each point has an elevation (height above sea level). This is called a heightmap — a grid where each cell stores a number representing the terrain height. The puzzle gives you this heightmap grid and a list of (x, y) coordinates. You look up the height value at each coordinate — those numbers are ASCII codes. Convert them to letters and you get the message.
Why this really exists: Heightmaps are how video games create realistic terrain — Minecraft, Skyrim, and every 3D world game uses them. GIS (Geographic Information Systems) uses them to model real landscapes for city planning, flood prediction, and agriculture. The USGS (US Geological Survey) publishes heightmap data for the entire United States. Even Google Earth uses elevation data to render 3D terrain.
A 2×2 heightmap grid:
1. Get the heightmap grid and coordinate list from puzzle data
2. For each (x, y) coordinate, read the height value at that position
3. Convert each height value to an ASCII character
4. Join characters → the answer word
💡 The data may be 1D (flat array) or 2D (nested array).
If 1D, convert to 2D using the grid width: grid[y * width + x].