.. or Picasso Tiles, these are made out of colorful transparent plastic, have magnets on sides and nicely connect into fences, cubes, domes. There's starter set

.. or Picasso Tiles, these are made out of colorful transparent plastic, have magnets on sides and nicely connect into fences, cubes, domes. There's starter set with a wheeled platform. Another nice detail is combining the colors to yield another color from the set.