Re: Up or Down
The bottom photo at:
http://www.martianspiders.com/objects144.htm
is a good example. It appears to be on the side of a hill so you can see the branches are lighter on the same side as the hill. One curious aspect is that some branches appear to have grown up the hill against gravity. This could mean the land has tilted as one possibility. The middle photos show some good example of longer spiders. Note how they look similar to gullies at lower latitudes. The spider branches are similar to the dunes often seen in these gullies suggesting they could be related.