This command will mark places on the mini map in the client connected to the
invoking character. It uses the normal X and Y coordinates from the main map.
The colors of the marks are defined using a hexidecimal number, same as the ones
used to color text in 'mes' output, but are written as hexadecimal numbers in C.
(They look like 0x<six numbers>.)

Action is what you want to do with a point, 1 will set it, while 2 will clear
it. Point number is the number of the point - you can have several. If more than
one point is drawn at the same coordinates, they will cycle, which can be used
to create flashing marks.

// This command will show a mark at coordinates X 30 Y 40, is mark number 1,
// and will be red.

viewpoint 1,30,40,1,0xFF0000;

This will create three points:

viewpoint 1,30,40,1,0xFF0000;
viewpoint 1,35,45,2,0xFF0000;
viewpoint 1,40,50,3,0xFF0000;

And this is how you remove them:

viewpoint 2,30,40,1,0xFF0000;
viewpoint 2,35,45,2,0xFF0000;
viewpoint 2,40,50,3,0xFF0000;

The client determines what it does with the points entirely, the server keeps no
memory of where the points are set whatsoever.