This one can be found at ground level... kind of.

It can be found right after a subtle transition in the terrain.

A transition where your footsteps no longer sound so crunchy.

The transition is marked by a small cluster of rocks.

You should be at the ground-level entrance to the treehouse area.

After the terrain changes, walk down to the right towards the water.

From the obelisk, head down to the ground-level entrance into the treehouse area.  After crossing the small cluster of rocks, walk down to the right towards the water.  The puzzle is a shadow on the ground.

The puzzle is blocked by so many spikes that you will need to go up into the treehouses to get an aerial view.  Go to the orange walkway that leads to where the laser is. 

Readjust the walkway so it leads to the left. It will take you all the way to the burnt tree.

Walk over to the burnt tree and look down at the ground.

-

When you get close to the water, you can see the puzzle on the ground.

Those spikes are annoying. They make it hard to trace the path. In fact, it almost seems... impossible to trace it. ;)

-

Perhaps this one can't be solved from any angle... on the ground, that is.

See if you can spot a place above ground level that might give you a fresh perspective.

Head up into the treehouses and find a good spot.

An orange walkway can take you to this spot.

You might have to readjust the orange walkways a bit.