Pythagoras Fractal Tree Macro: Recursive Right-Triangle Construction

Pythagoras Fractal Tree Macro: Recursive Right-Triangle Construction
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2021-01-26 12:31
This GeoGebra macro demonstrates how a Pythagoras-based fractal tree is generated by repeatedly constructing and attaching right-triangle shapes using consistent side-length and angle rules. The key math concepts are the Pythagorean-triangle relationship as the guiding idea for scaling, trigonometry for determining connection angles, and geometric transformations that reuse local reference points to grow the figure step by step. Construction-wise, it creates polygonal (triangle) components with Polygon and tracks their defining vertices using Point/Vertex; it uses Centroid to obtain reference locations for each stage; it measures lengths via Length to control scaling; it computes angles with Angle to set the correct orientation; and it applies Translate to move newly created parts into position for the recursive “tree” growth. The example is driven by a control like button1 and uses stored objects such as A, B, C, D and auxiliary points/values (e.g., VC, VD, CR/CL, dL/dR, side, angR/angL, sR/sL, poly1) to manage geometry and parameters. Suitable for middle/high school through early university lessons on geometry construction, recursion, and fractal visualization.

GeoGebra Commands & Parameters

  1. Polygon(A, B, 4) → s, f, g, h, i, C, D
  2. Centroid(s) → C0
  3. Vertex(s, 3) → VC
  4. Vertex(s, 4) → VD
  5. Point(Semicircle[VD, VC]) → F
  6. Centroid(Polygon[F, VC, 4]) → CR
  7. Centroid(Polygon[VD, F, 4]) → CL
  8. Length(Segment[VD, F]) → dL
  9. Length(Segment[VC, F]) → dR
  10. Angle(F, VC, VD) → angR
  11. Angle(VC, VD, F) → angL
  12. Translate(Rotate[Dilate[s, dR / side, C0], (-angR), C0], Vector[C0, CR]) → sR
  13. Translate(Rotate[Dilate[s, dL / side, C0], angL, C0], Vector[C0, CL]) → sL
  14. Polygon(E, G, 4) → poly1, j, k, l, m, H, I

AI Drawing Prompt Reference

Draw a recursive right-triangle tree based on the Pythagorean theorem. The figure consists of multiple right triangles connected by consistent side lengths and angles. The construction order starts with a basic triangle and then recursively adds new triangles, using centroid, length, and angle to position and scale new parts. The figure should appear as a branching tree with multiple triangle nodes and connecting lines.
The prompt above was compiled from the original drawing commands and is for reference only.