Usually, when I'm signing generically about middle schools, I use the MIDDLE+SCHOOL sign. If I'm signing about a particular local school I use the initials in loan-sign form, such as making a semicircle with the letters, like the way U-S-A is done. Suppose the name of the school is Charleston Middle School, it would be C-M-S, made in a slight arch, with the M being at the peak. The students identify it that way since they see "CMS" posted all over the school walls, websites, letterhead, t-shirts, etc.
