fitting text into rectangle

[tsh73]

It happened as part of student task.
Given a string, set it inside a matrix,
then do some transforms on this matrix (line swaps etc)

First question is, what size that matrix should be?

Some testing shows it should be near square, around sqr(len(txt$))+1 size.

So yo can do things like this
Mine i
s a lo
ng and
a sad
tale!


or that ;)
Just BASI
C is an e
asy and p
owerful p
rogrammin
g languag
e for Win
dows.____


and of cource
SATOR
AREPO
TENET
OPERA
ROTAS


'text to grid
'given a text, get size of minimal rectangular grid it fits

goto [skipTest]
for l = 1 to 100
   m = int(sqr(l))
   m=m+(m*m<l)
   print l, m, m*m,
   call findMinRect l, minW, minH
   print minW, minH, minW* minH, int((m*m-minW* minH)/(m*m)*100);"%"
next

[skipTest]

print
txt$="Mine is a long and a sad tale!"
print txt$
call findMinRect len(txt$), minW, minH
gosub [printRect]

print
txt$="Just BASIC is an easy and powerful programming language for Windows."
print txt$
call findMinRect len(txt$), minW, minH
gosub [printRect]

end

[printRect]
c=0
for i = 1 to minH
   for j = 1 to  minW
       c=c+1
       c$=mid$(txt$,c,1)
       if c$="" then c$="_"    'then out of string, should use spaces (but they are invisible)
       print c$;
   next
   print   'new line
next
return

sub findMinRect txtLen,byRef minW, byRef minH
   m = int(sqr(txtLen))
   m=m+(m*m<txtLen)

   minS=1e6
   found = 0
   for h = 2 to m  'I want it al least 2 lines
       for w = 2 to m
           s=w*h
           if s>=txtLen then found = 1: exit for
       next
       if found then
           if s<minS then minS=s: minW=w: minH=h
       end if
   next
end sub