edit edit edit!!!! this is of course the wrong airfield! You were refering to this one number 4 ?http://images.google.ca/imgres?imgur...ada)%26hl%3Den
but this is still of interest !
The marks seem to align with the runways. Take a look at the airfield plan http://www.nevadadot.com/traveler/av...ms/pdf/TPH.pdf
based on this I reckon its a;
Airport wind direction and velocity indicator United States Patent 5323649
A tetrahedron-shaped airport wind direction and velocity indicator being triangular in cross-section with first and second sides sloping downward from a top edge, such sides coming to a point at the front of the device with the device adapted to point into the wind. The device has illuminable numerical indicia for displaying wind speed on its first and second sides and illuminable side edges for night time viewing of the device from above with the direction of the device indicating wind direction.