to  -- Command, special form, see below.
     This command takes a variable number of inputs.  The first is the name
     of  a  procedure to be defined.  The rest, if any, must be preceded by
     colons, and are the names of variables to be used  as  inputs  to  the
     procedure.   Logo  responds  to  the to command by printing a "greater
     than" sign (>) prompt, to show you that you are defining  a  procedure
     rather  than  entering  commands to be executed immediately.  You type
     the instruction lines which make up the definition.  When you are done
     with  the  definition,  type the special word end on a line by itself.
     For example:

     _ˆ*to twoprint :thing
     _ˆ>print :thing
     _ˆ>print :thing
     _ˆ>end
     _ˆ*

     This example shows the definition of a procedure named twoprint, which
     has  one  input, named thing.  The procedure you are defining with the
     to command must not already be defined.
