Introduction
Constructional praxis is a broad concept which has been applied to a number of rather different types of activities. These activities have in common the characteristic that they require a patient to assemble, join, or articulate parts to form a single unitary structure. However, they may differ from each other in many respects, e.g., in complexity, in the type of movement and the degree of motor dexterity required in achieving the task, in the demands made on the higher intellectual functions, and in whether they involve construction in 2 or 3 spatial dimensions.The most elementary constructional praxis tasks involve the utilization of 1-dimensional units to form rather simple 2-dimensional structures such as making a design out of sticks or building a simple vertical structure (e.g., tower, cross, pyramid) out of blocks. However, the difficulty of this type of task can be augmented to any desired level by requiring