Question: print(plots[display](seq(seq... ...)): works fine! Why??

Short question version:

print(plots[display](seq(seq...   ...)):  works fine!  Why??

Longer, more detailed question:
  print(plots[display](seq(seq...   ...)):   This Maple statement ends in a colon - so I would not have expected any output.  I'm using "pretty" print, as opposed to printf, because it automatically centers the output

    This question is actually an extension of one I posed  yesterday, under the title "How to clear Maple output" - but the question I should have been asking is: "Why is the previous output not automatically cleared?"  The main points of that question are stated below.  Any comments, suggestions gratefully received.

   David

"How to clear Maple output"

I'd like to know how the screen previous ouput can be cleared.   ...or what is the likely cause.

   At the start of my program I have:

restart;
interface(echo=0, verboseproc=0, warnlevel=0, prettyprint=1):

#I thought restart; would automatically have cleared any previous output.

The program reads necessary input (eg no of players, ..)  using:

x:=readline(terminal):