メモリが面になっている定規です。10mmピッチでアクリルパーツが接着されており接着面がメモリになっています。そのため様々な視点から物の長さを測ることができます。

Dimension Scale - Motonori Katsuyama

This scale can easily measure from any angle accurately. Its tick mark is colored red at 10mm pitch. The tick mark is not printed on the surface. The acrylic parts consisting of this scale are bonded together. This scale was made by Miyuki Acryl in Tokyo. They have high technique of making various acrylic products.