GDSPLOT supports special fill patterns for contact and via layers. This is a "transparent" fill that enables the designer to see through a contact. It is especially useful for plotting devices that have "stacked" contacts or vias.

The three types of contact fills are:

[1] An x through the square or rectangular contact.

[2] A plus sign.

[3] A diamond.

In the lower row you can see how these appear when vias or contacts are stacked.