┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Arial:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Helvetica:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Code2000:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Courier:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Andale Mono:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Caslon:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Arial Unicode MS:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

Lucida Grande:

┏┯━┳━━━━━━━┓
┃│☺┃  ╲    ╭╮ ┃
┃╰─┨    ╳  ╰╯ ┃
┗━━┻━━━━━━━┛
0123456789abcdef01234

From looking at the Unicode tables and the above my conclusion is that using Unicode characters rather than plain ASCII can make figures look a lot better, but it's not really possible to express significantly different shapes: like ASCII, Unicode is limited to (mostly) straight horizontal vertical lines. This is an HTML file. It uses a META tag to set the UTF8 characterset but this doesn't seem to work, probably because the server adds an ISO-8859-1 header by default, so I also use PHP to send a header to indicate UTF8 encoding. Note that in HTML, multiple spaces are collapsed into a single space, and in many fonts regular spaces may vary in width. For this reason, it's important to choose an alternative space character (Unicode has nearly 20 spaces.) In this example I used the U+2007 FIGURE SPACE that is supposed to be the same width as digits. It generally isn't so a monospace font must be used. Iljitsch van Beijnum