I realized why that theme remided me of the original Myst game. There were pages
you had to collect that look extremely similar to that page with the folded corner.
One of the levels, the Mechanical Age, had a building with geared turnstiles that
look very similar to the gears icon. The arrow icon on the Todo application looks
like the cursor did, when you wanted to turn around (reverse your direction). The
color scheme, hand drawn entities, and the attention to the smallest detail also
lends to creation of a pleasing user experience. And I just noticed that that mask
icon on the task bar, is similar to a tribal mask that was on the wall of one of the
rooms. I'm sure I could go on, but again I this work is really great...