Eureka Back to School Dr. Seuss Cat in the Hat Postcards for Teachers, 4'' W x 6'' H Includes (36) identical Dr. Seuss postcards. Each Dr. Seuss postcard measures 4'' W x 6'' H. Let parents know how well their children are doing in school by sending them a mailable Dr.Seuss Postcard. Use this colorful teacher stationary to send notes to home, organize parent teacher meetings, keep in touch with students, and more! These cards are a fun inexpensive way for teachers to stay in touch with students and parents and the back looks like a standard postcard so a personal message can be added.