Hey Marigold, I've been thinking about building a tiny ecosystem puzzle where each plant type follows a rule, and you can see how invasive species might spread. Interested?

Sounds good—I'll outline a set of planting rules that let each species compete fairly, but keep an eye on the boundaries so the invaders don’t sneak in. Let me know if you want the diagram or just the algorithm.

Here’s a simple grid you can copy into your diary. Each letter represents a plant, and the border lines show the lawnmower’s path. The rules are: A = native grass, B = daisies, C = ivy (invader), D = native shrubs Rules: 1. Ivy (C) can only move to an adjacent square if the square is not a grass (A). 2. Grass (A) will spread to any empty adjacent square unless a shrub (D) blocks it. 3. Daisies (B) can’t be adjacent to ivy (C). 4. Shrubs (D) are fixed; they block both grass and ivy spread. ``` A A A B B A C A D A B A A A A A D A C A B B A A A ``` - The mower follows the dotted line across the middle row. - Watch the C’s—if you see a C on the left of a B, it’s a potential slip. - After mowing, you’ll have the chance to check that the B’s haven’t been surrounded by C’s. Keep a note of any new C’s that appear after each mowing session, and you’ll spot the invasion early. Good luck, and don’t let that ivy get the last word.