Planes in three dimensions

...and points

Specify any four numbers \( a, b, c, d \) and view the plane with equation \( ax + by + cz = d \). You can also specify two points \( P \) and \( Q \), with options to draw a normal vector \( \vec{n} \) to the plane based at \( P \) (this only looks good if \( P \) is chosen to be on the plane) and the vector from \( P \) to \( Q \). Additionally, you can alter the range of variables \( x, y, z \).

Click the "Activate" button. If you change any of the entries or check/uncheck any boxes, you'll need to click the "Update" button to see the changes.