OBLO is a 3D puzzle made of differently sized, shaped and colored spherical elements that need to be twisted against the central axis in order to disassemble and fully reassemble the toy. It consists of an outer round layer (the container), a lid and 10 removable pieces. OBLO is coloured with three primary colours and one secondary colour to appeal to its audience, children between the ages of two and five.

In order to successfully progress from one level to the next, the child needs to find the correct orientation for each piece that will enable their smooth passage through the fixed opening in the outer layer. Using this method, the spherical elements work as part of a bigger unity. The link that connects all the pieces is their shape, which matches the opening in the outer layer.

The degree of difficulty can be modified for different age groups. To make OBLO easier, the open space in the outer layer can be enlarged. On the contrary, the difficulty level can be increased by using a larger variety of shape types. Also, the number of layers can be increased by reducing the thickness of each layer or by modifying of the diameter of the outer layer itself. Colours can also influence the degree of difficulty. Designed by Marco Paclovic.