dont get it att all. just woth trying add some different places. but why and how it worked did not undesten. readet like 2- 3 books , and many websites. and do not get it. ain this level not explanation befor task. garbage cleaner, how it works. but how works static , and array list. i find array in books and try it but there array list before i undestad it why my task didnt pass i spen couple days. i have idea thas will be the same problems. not exploration. how about robot ? that learneng in codegym, he would did not understand he dont have books. and other robot must tell him on their language.