ASCI art characters for creating diagrams
Characters:
Single line

    ASCII code 191 = ┐ ( Box drawing character single line upper right corner )
    ASCII code 192 = └ ( Box drawing character single line lower left corner )
    ASCII code 193 = ┴ ( Box drawing character single line horizontal and up )
    ASCII code 194 = ┬ ( Box drawing character single line horizontal down )
    ASCII code 195 = ├ ( Box drawing character single line vertical and right )
    ASCII code 196 = ─ ( Box drawing character single horizontal line )
    ASCII code 197 = ┼ ( Box drawing character single line horizontal vertical )
    ASCII code 217 = ┘ ( Box drawing character single line lower right corner )
    ASCII code 218 = ┌ ( Box drawing character single line upper left corner )
    ASCII code 179 = │ ( Box drawing character single vertical line )
    ASCII code 180 = ┤ ( Box drawing character single vertical and left line )

Double line

    ASCII code 185 = ╣ ( Box drawing character double line vertical and left )
    ASCII code 186 = ║ ( Box drawing character double vertical line )
    ASCII code 187 = ╗ ( Box drawing character double line upper right corner )
    ASCII code 188 = ╝ ( Box drawing character double line lower right corner )
    ASCII code 200 = ╚ ( Box drawing character double line lower left corner )
    ASCII code 201 = ╔ ( Box drawing character double line upper left corner )
    ASCII code 202 = ╩ ( Box drawing character double line horizontal and up )
    ASCII code 203 = ╦ ( Box drawing character double line horizontal down )
    ASCII code 204 = ╠ ( Box drawing character double line vertical and right )
    ASCII code 205 = ═ ( Box drawing character double horizontal line )
    ASCII code 206 = ╬ ( Box drawing character double line horizontal vertical )

Shading

    ASCII code 176 = ░ ( Graphic character, low density dotted )
    ASCII code 177 = ▒ ( Graphic character, medium density dotted )
    ASCII code 178 = ▓ ( Graphic character, high density dotted )
    ASCII code 219 = █ ( Block, graphic character )
    ASCII code 220 = ▄ ( Bottom half block )
    ASCII code 223 = ▀ ( Top half block )
    ASCII code 254 = ■ ( black square )