`val round_rect : Num.t -> Num.t -> Num.t -> Num.t -> Path.t`

`round_rect w h rx ry` returns a rectangle of width `w` and height `h` with rounded corners. The rounded corners are arcs of an ellipse of radii `rx` and `ry`. `rx` (resp. `ry`) should be positive and smaller than `w/2` (resp. `h/2`).

`val rectangle : Num.t -> Num.t -> Path.t`

`rectangle w h` returns a rectangle of width `w` and height `h`.

`val ellipse : Num.t -> Num.t -> Path.t`

`ellipse rx ry` returns an ellipse of great axis `rx` and small axis `ry`. The ellipse is centered on the origin and aligned with the x axis.

- parameter fill

  the color with which to fill the ellipse ; if no color is provided, it is not filled.

- parameter stroke

  the color with which the ellipse's outline shall be drawn ; default is black.

- parameter thickness

  the thickness of the pen used to draw the outline ; 1. is default

`val circle : Num.t -> Path.t`
`val patatoid : Num.t -> Num.t -> Path.t`

See `Box.patatoid`.

`val patatoid2 : Num.t -> Num.t -> Path.t`

See `Box.patatoid2`.