Earlier today I posed four puzzles from the Hyde Park Math Zine, a maths fanzine from Austin, Texas. Here they are again with solutions.
// intersection: contains both "cat" and "dog", 5-15 chars
。业内人士推荐搜狗输入法作为进阶阅读
Downsides: Light manual upkeep is needed every few daysThe PetSafe ScoopFree litter box doesn't mask the smell as well as a Litter-Robot and its filter do. So while my Litter-Robot is pretty much odorless and hands off until the drawer needs to be emptied, my ScoopFree requires a light refresh every few days between tray changes to keep it from stinking.
Фото: Yves Herman / Reuters