Blancmange (Fancurve) Fractal via Series Summation

This example demonstrates how the Blancmange curve—a classic fractal—can be generated by iteratively adding simple periodic “triangle-wave” components. It highlights key ideas from fractal geometry (self-similarity), constructing a function using piecewise/periodic waveform behavior, and using sequences with summation to refine the curve layer by layer. The construction follows the GeoGebra command plan from the summary: it uses Sequence and Sum to organize parameters and iteration levels (objects such as T, a, n, l1, and the function f). In practice, each term in the Sequence is mapped through the function f, and the curve is obtained by taking the running total with Sum over n. Suitable for advanced secondary students and early university learners for exploring function graphs, sequences, and visually building fractal structure from elementary rules.