m = {1 => ""}
r = 1
rd = {1 => 0}
(1..100).each do |c|
  mof = c % 5 == 0
  mot = c % 3 == 0
  if mot && !mof    
    rd[r] += 1
    c.to_s.length.times { m[r] << " "} unless rd[r] == 2
    r += 1
    if m[r].nil? #newline
      m[r] = ""
      rd[r] = 0
      (m[r-1].to_s.length - c.to_s.length).times { m[r] << " " }
    end
  elsif mof && !mot
    c.to_s.length.times { m[r] << " "}  
    r -= 1
  end
  
  c.to_s.length.times { m[r-1] << " " } if r != 1 &&  !mot &&  rd[r-1] != 2
  c.to_s.length.times { m[r+1] << " " } if !m[r+1].nil? &&  !mof
   
   m[r] << c.to_s
end

(1..15).each {|i| puts m[i].to_s}