Numbers as database
Widgets like SVG suite use sequences of numbers as a database to indicate the single coordinates of every point.
The widgets are:
The path tag is one of the basic SVG shapes (path, line, polyline, polygon, circle, ellipse, rectangle, text, image).
The path is written as a sequence of numbers that indicates the coordinates of a closed line both positive and negative. You can try the code below saving it as triangle.svg. (on the right you can see the result)
Path (more complex)
This is a more complex example of a path, a positive shape (the heart), and negative (the circle in the middle), and another two separated shapes.