Geometries are collinear if they lie on the same line and coplanar if they
lie on the same plane. collinearity can be tested between two curves or three
points, weighted points, circles, or spheres. coplanarity can be tested
between two surfaces or 4 points, weighted points, or spheres

```
collinear(x, y, z = NULL)
coplanar(x, y, z = NULL, t = NULL)
```

## Arguments

- x, y, z, t
Vector of geometries.

## Examples

```
# Collinear points
collinear(point(0, 0), point(1, 1), point(2, 2))
#> [1] TRUE
# Coplanar triangles
coplanar(
triangle(point(0, 0, 0), point(1, 1, 1), point(1, 1, 0)),
triangle(point(0, 0, 0), point(-1, -1, -1), point(-1, -1, 0))
)
#> [1] TRUE
```