This is a delightful holiday thing to make with your 3D printer. Thank you Thingiverse contributor ”Pleppik” for designing this 3D printed advent calendar puzzle. There will be 25 puzzle pieces in the shape of a block (one for each of the 25 days leading to December 25th). Each block has a custom formed slots to insert a differently shaped gift. All of these blocks fit perfectly together and form a Christmas tree, sort of like Legos! We have been 3D printing these blocks with ABS 3mm filament (interesting fact: ABS is the same material the Legos are made with).