stop_motion.rb

$grid = Array.new(10, "X").map { |r| Array.new(10, "X") }

def $grid.print
  puts map(&:join)
end

def $grid.draw(row, col, size: 2)
  bounds = $grid.length
  fail "out of bounds #{row}+#{size} > #{bounds}" if row+size > bounds
  shape = ' '

  size.times do |i|
    $grid[row][col + i] = shape
    $grid[row + i][col] = shape
    $grid[row + i][col + i] = shape
  end
end

$grid.draw(5, 5)
$grid.print

hello

$grid = Array.new(10, "X").map { |r| Array.new(10, "X") }

def print
  puts $grid.map(&:join)
  # also could do:
  # puts $grid.map { |array| array.join(' ') }
end

def draw(row, col, size: 2)
  bounds = $grid.length
  fail "out of bounds #{row}+#{size} > #{bounds}" if row+size > bounds
  shape = ' '

  size.times do |i|
    $grid[row][col + i] = shape
    $grid[row + i][col] = shape
    $grid[row + i][col + i] = shape
  end
end

draw(5, 5)
print