2nd handwritten character rubber stamp "Mathematical formula" by Lamp x Paperi. It is designed to look like a scientist has scribbled a formula in a notebook. All Lamp x Paperi products are handmade in small batches by the designer Hiroko Uno in their Kyoto studio.
Photos (c) Lamp x Paperi and Jonna Studio
Other items in the photos are not part of the listing.
Designed and hand-crafted in Japan.