Vocabulary consisting only from characters you are able to read
角形
かくけい
(1)(N)-cornered polygon, incl. triangle, (2)Japanese rectangular envelope (opening on the short dimension; numbered 0-8, A3, A4, each with different sizes); mix
課
か
(1)lesson/ (2)section (in an organization)/division/department/(ctr) (3)counter for lessons and chapters (of a book)/(P) leda1
交流
こうりゅう
(1)(cultural) exchange, interchange, interaction, (inter-) mingling, (social, etc.) networking, intercourse, (2)alternating current, AC suru