Draws a quadratic bezier curve from the current location, though the
two given points.

The current position is then set to the point defined by the
`x2` and `y2` parameters.

## Parameters

`x1`
x-coordinate of the first point.

`y1`
y-coordinate of the first point.

`x2`
x-coordinate of the second point.

`y2`
y-coordinate of the second point.

## Return Values

No value is returned.