This is a really great way to make your Super Mario themed bedroom both practical and fun. All you need to do is buy some yellow boxes from IKEA, and insert them into an IKEA Kallax shelving unit. Download the question mark template below, print it out onto thick photo paper or thin card, carefully cut out the question mark and the holes for the corners, then spray mount onto the front of the storage boxes. It should turn out looking something like this! Easy, and all for less than £40. UPDATE: Ikea no longer make this box in yellow - however you can still buy it in white and spray it yellow. Please scroll down to see other options though! IKEA KALLAX Shelving unit £20 IKEA TJENA Yellow Storage Box £4 Super Mario Question Mark Block Template PDF UPDATE! IKEA now make the Kallax unit with bright yellow doors. If you can afford it - this is a better idea, as the doors will last much longer than the Tjena boxes above. IKEA Kallax Storage shelfing unit with doors IKEA Kallax Yellow Door Insert