Abstract: A geometric construction device forms circles or arcs with a marking instrument and simultaneously measures angles. The device includes a radius arm and a rotatable member. The radius arm includes a means for receiving the marking instrument and a disc having a pivot point and being rotatable about the pivot point. The disc is used to attach the rotatable member to the radius arm. The rotatable member in combination with the radius arm forms a 360° protractor. The rotatable member has a plurality of radius holes in it for receiving the marking instrument. These radius holes may be used to form circles or arcs with the radius being less than or equal to the radius of the disc. The 360° protractor is capable of measuring degrees between 0° and 360° while circles or arcs are being formed.

Abstract: The present invention provides a three-dimensional geometric puzzle having a cube element, five triangular prism elements and a parallelepiped element. Each one or all of the elements of the puzzle are capable of being oriented such that they have a thickness equal to the length of an edge of the face of the cube element. The elements can also be juxtaposed in a predetermined fashion to form various geometric solids, such as a parallelepiped having a square face and a height equal to the length of a side of an edge of the cube element.