This figure uses overlapping circles to illustrate hidden terminals. The two wireless stations are labeled H1 and H2 and each is represented by a light blue circle. These two circles overlap but just barely, creating a sliver of common area that is shaded dark blue. At the center of this dark blue area is the access point, labeled AP, and represented by its own blue circle that is superimposed over the other two. This third circle overlaps both H1 and H2 at about their center points, leaving half of them within the AP's circle and half without. Where they overlap, this area is shaded in a medium blue. Looking left to right we see the light blue of H1, the medium blue of AP and H1's overlap, the dark blue of the overlap of all three, the medium blue of AP and H2's overlap, and the light blue of H2.