[orx-marching-squares] Add demo texts.

orx-marching-squares/src/jvmDemo/kotlin/FindContours01.kt

@@ -3,6 +3,22 @@ import org.openrndr.color.ColorRGBa
 import org.openrndr.extra.marchingsquares.findContours
 import org.openrndr.math.Vector2
 
+/**
+ * A simple demonstration of using the `findContours` method provided by `orx-marching-squares`.
+ *
+ * `findContours` lets one generate contours by providing a mathematical function to be
+ * sampled within the provided area and with the given cell size. Contours are generated
+ * between the areas in which the function returns positive and negative values.
+ *
+ * In this example, the `f` function returns the distance of a point to the center of the window minus 200.0.
+ * Therefore, sampled locations which are less than 200 pixels away from the center return
+ * negative values and all others return positive values, effectively generating a circle of radius 200.0.
+ *
+ * Try increasing the cell size to see how the precision of the circle reduces.
+ *
+ * The circular contour created in this program has over 90 segments. The number of segments depends on the cell
+ * size, and the resulting radius.
+ */
 fun main() = application {
     configure {
         width = 720