Much thanks goes out to Scott H. who brought attention to these amazing clips of Glass Sesame Street pieces on youtube.
According to Muppet Wiki:
"In 1977, Glass wrote a series of short vocal and instrumental pieces for Sesame Street. These include a series of animated films which employ geometric curves traced to various points on a circle to reveal other geometric shapes and colors. These works very closely resemble the "Dance" numbers written during the same time period as his Einstein on the Beach opera."