fractal curves generator

This is an:
- line fractal generator
- coding experience

Line fractal generator
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It is a fractal generator what can use all the curver from the book http://www.fractalcurves.com/HorrorVacui.html

There is some simple parameter:
- Width: width of the line
- Height: height of the line
- Length: base length of the curve. the length of the pattern in the 0. iteration
- Deep: number of iteration
- Grid: grid type of the pattern: can be "square", or "triangle"
- Mode: drawing mode, can be "line" or "spline". "Line" is faster, but "spline" look better
- Steps: in the "spline" drawing mode how many segment need to draw the curve.
- Pattern: pattern of the line. It is a two dimensional array, it is the same as the "segment values" in the webpage (without line number)

The preview can be fast but the rendering is very slow (a 6 deep line with spline take about 5-6 hour, a 8 deep with line take about 3-4 hour)

Coding experience
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