Yes, regarding the implicitplot comment that doesn't exist in that 2008 thread.  It was me who made an implicitplot answer (I thought it was quite an original idea and not a bad one at that either) and then sadly deleted my post due to the dissappointingly high number of down thumbs to my answer.  A great celebration ensued following the demise of the downthumbs ... so if anyone's wondering about Robert Israels mysterious reference to an implicitplot answer, you now have it.

Actually it was me who posed that question (custom symbols) back in 2010.  The answer I got was no, it cannot be done. 

Always a workaround though, you could always create your own plot object and use them at your specified pointplot coordinates.  Won't work for symbol but the workaround is probably good enough.

Actually it was me who posed that question (custom symbols) back in 2010.  The answer I got was no, it cannot be done. 

Always a workaround though, you could always create your own plot object and use them at your specified pointplot coordinates.  Won't work for symbol but the workaround is probably good enough.

I believe there was a thread about this in the last year or so.  I think links were provided, I'm almost sure a zip file was provided as well.  If not a repost here would probably be appreciated.

That error is because I forgot to write in the with(plots) command.

Since I didn't include with(plots): I should have written b:=plots[pointplot]([xs,ys])

sorry bout that.

That error is because I forgot to write in the with(plots) command.

Since I didn't include with(plots): I should have written b:=plots[pointplot]([xs,ys])

sorry bout that.

I too was interested by the title of this question.  It might be interesting to start a real question with the same Title.

I was burned once for not choosing a title that did not appropriately address the content of my question.  I would try to branch this question but branching does not work for me.  Although I do not have answers for the question you pose I could start off some ideas for the Title :) and maybe someone could branch this question for me as I cannot

How to count grains of sand in a heap -

I think we could start to make a couple of assumptions. 
1/ The pile of sand falls in a cone.
2/ All grains of sand are either the same size (0.5mm) or fall into some size normal distribution of 0.5mm to 2mm.

Some interesting ideas come from this problem.  Again, some more assumptions, the grains are nearly circular shapes as opposed to irregular shapes.  Given if the shapes are circular there would exist a maximum space that could exist between the grains and as a result give the minimum number of grains in the pile (as an example of marbles stacked in an array all at 90 degrees to each other) similarily a minimum space could exist which would describe a possible maximum number of grains in the pile (as there is no outer boundary to be confined, it is highly possible that the grains of sand fall into a closely packed scenario - what is the probability that they do?) as the example of marbles stacked in a pyramid having spaces at a minimum. 

Of course using marbles makes it easy... So there you have it.  Sorry I have no Maple input at the moment but I thought I'd get the marbles rolling so to speak.

@acer I didn't even see you had posted a solution until this morning.  I must have been compiling and submitting while you submitted yours, of course the caveats of dialup internet doesn't allow me to see things immediately.  Funny we arrived at something similar. 

I'm not sure the O.P. had DE in mind.  It could make sense though. 

@acer I didn't even see you had posted a solution until this morning.  I must have been compiling and submitting while you submitted yours, of course the caveats of dialup internet doesn't allow me to see things immediately.  Funny we arrived at something similar. 

I'm not sure the O.P. had DE in mind.  It could make sense though. 

Aren't Maplesoft and RIM practically next door neighbors?  However a blackberry being more business audience focussed I can see why you opted to the ipad, because it plays out to a much bigger audience.  I do not own anything apple/mac .. at least not yet, I heard a business commentator mention after Steve Jobs passed away that he would be surprised if Apple was still around in 10 years ... just something I heard in the last week but also to be taken with a grain of salt.  Will the maple player work on the blackberry? 

@Joe Riel 

The command to reproduce the error using a very simple proc to illustrate

a:=proc(L)
  global i:
  i:=nops(L):
  if i<50 then print("Small list") else print("Large list") end if:
end proc:

a := subs( (i < 50) = (i < 30), eval(a))
             Error, `=` unexpected

@Joe Riel 

The command to reproduce the error using a very simple proc to illustrate

a:=proc(L)
  global i:
  i:=nops(L):
  if i<50 then print("Small list") else print("Large list") end if:
end proc:

a := subs( (i < 50) = (i < 30), eval(a))
             Error, `=` unexpected

That seems similar to the knapsack problem.

Unless of course I renamed a built-in proc in order to substitute - then crtl-z won't matter.

Thanks for the global declaration.  But why should local declarations matter when I'm trying to sustitute into the proc itself?  But I guess the eval in the subs command is the precursor for the reason.

Unless of course I renamed a built-in proc in order to substitute - then crtl-z won't matter.

Thanks for the global declaration.  But why should local declarations matter when I'm trying to sustitute into the proc itself?  But I guess the eval in the subs command is the precursor for the reason.