Summary

Inspired by the recent popularity of ASCII art challenges, this challenge's purpose is to draw an ASCII checkerboard, like one on which Chess can be played.

Write a program that takes a positive integer n as an argument, in stdin, or as user input, and output an checkerboard with nxn squares, along with a border that is 1 character thick.

Each square should be 2x2 characters. The squares should follow the normal alternating white-black (white first, as in top-left corner) pattern of a checkerboard. White squares should be made out of space () characters, and black squares should be made out of pound (#) characters.

The border should be made out of dashes (-) with a plus (+) on the border or perpendicular point of a square.

Input

Positive integer in representing the number of squares (dimensions in squares) to draw in the checkerboard, with each square being 2x2 characters.

Example Results

n=2

+--+--+
| |##|
| |##|
+--+--+
|##| |
|##| |
+--+--+

n=3

+--+--+--+
| |##| |
| |##| |
+--+--+--+
|##| |##|
|##| |##|
+--+--+--+
| |##| |
| |##| |
+--+--+--+

n=4

+--+--+--+--+
| |##| |##|
| |##| |##|
+--+--+--+--+
|##| |##| |
|##| |##| |
+--+--+--+--+
| |##| |##|
| |##| |##|
+--+--+--+--+
|##| |##| |
|##| |##| |
+--+--+--+--+

... and so on.

Notes

• Trailing spaces and new lines are acceptable.
• You may write either an entire program or a function.
• No leading spaces.
• Your program should display correct results for n=15.
• For less-known esoteric languages and similar, provide a link to the language.
• n=0 should produce +. (optional, but highly recommended and encouraged.)
• Shortest code in bytes wins, as this is code golf.