CONST allows you to set certain construction 
parameters using various construction options.

Choose from the following options:

PLANE   - to define the desired construction plane. This
          option is also assigned an Immediate Mode 
          command.

DEPTH   - to change the working depth at which entities 
          are created (when depth is used for creation) 
          by adding a specified value to the current 
          working depth.

2D/3D   - to select two-dimensional or three-dimensional
          mode for various geometric modeling functions, 
          the Position Menu, and CADL point and line 
          coordinate output.

L-LIMIT - to choose whether to create lines to the length 
          of the current viewport limits, or limit line 
          length to the selected line creation methods 
          such as angle, endpoints, parallel, and tangent.
