Celebrating the Ancient Peoples of the World
The peoples of the Fremont Culture inhabited parts of Utah, Nevada, and Colorado at about the same time that the Ancestral Puebloans were inhabiting the area to the south (roughly 0 - 1300 CE).
There are several styles of Fremont art and Fremont used a variety of techniques to accomplish their task. Note for instance, the glyph below which uses negative (empty) space instead of an outline and the left image in the photo to the left which employs a variety of positive and negative space techniques. Both of these glyph photographs were taken at McConkie Ranch.

Some sites, like the Hovenweep National Monument Sites extend across state lines (apparently the early people did not recognize that there would be state lines in the future). See the Colorado page for additional photos from Hovenweep.