I really like these two type examples. I like how the the dot of the "i" fits into the bottom of the "t" and how some of the colors are swapped like the black portion of the "s" in the word this and the blue portion of the "e" in the word next. The "x" is probably my favorite letter. I also enjoy how tightly kerned the whole piece is.

The word LACK here is great. Your eye adds the parts of the words that are missing or "lacking" like the K stem. This is possible to visualize because the C serifs are so straight and flat, it creates a line with the negative space. The L bracketed serif is so exaggerated it bleeds into the A and becomes the left stroke. It is simple, but it really caught my eye.