Here are some impressions from the Joint Block Seminar 2023 of the Graduate School IRTG of our SFB-TRR 195. The focus of the school was Category Theory, it was mainly organized by Fabian Mäurer, Liam Rogel and Erec Thorn and took place in Trippstadt from the 18th to 22nd September 23 with more than 25 participants.