Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: From Pop-Up Cards to Coffee-Cup Caustics: The Knight's Visor   As a pedagogical exercise, we derive the shape of a particularly elegant
pop-up card design, and show that it connects to a classically studied plane
curve that is (among other interpretations) a caustic of a circle.

23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph