A piece of three-dimensional maze and freely-constructible 3d maze

A U-shaped piece used for creating a three-dimensional maze, comprising:

• a first flat plate;
• a second flat plate connecting to the first flat plate at right angles;
• and
• a third flat plate connecting to the second flat plate at right angles on the side opposite to the first flat plate so as to face the first flat plate,
• wherein the three flat plates forms a continuous opening on continuous three opening faces of a cube, the cube having the three flat plates and the three opening faces, the continuous three opening faces directing to different three directions, and defining a path through the opening,
• wherein two ridgelines between the opening faces of two adjacent opening faces of the cube, each ridgeline does not exist in the opening faces of the three opening faces so that the path is opened outward.

A corner piece used for creating a three-dimensional maze, comprising:

• a first flat plate;
• a second flat plate connecting to the first flat plate at right angles;
• a third flat plate connecting to the second flat plate at right angles on the side opposite to the first flat plate so as to face the first flat plate;
• and
• a fourth flat plate connecting to each of the first, second, and third flat plates at right angles on a side perpendicular to the first, second, and third flat plates,
• wherein the four flat plates forms a continuous opening on continuous two adjacent opening faces of a cube, the cube having the four flat plates and the two opening faces, and defining a path through the opening,
• wherein a ridgeline between the two adjacent opening faces of the cube does not exist so that the path is opened outward.