back to school groovy a4 postcards set in retro 70s style. psychedelic poster hippie with retro catroon

set character groovy psychedelic cartoon teacher school globe illustration back education hippie hand 70s poster retro vector study colorful student graphic paper book learn stationery apple knowledge isolated class lettering collection banner hipster text board sticker doodle vintage elementary art supplies sketch best explore grow a4 background 80s design