class Glyph:
    # ...
    def svg(self, **kwargs):
        unit = kwargs.get('unit') or SVG_OPTIONS['unit']
        outer_color = kwargs.get('outer_color') or SVG_OPTIONS['outer_color']
        inner_color = kwargs.get('inner_color') or SVG_OPTIONS['inner_color']
        outer_thick = kwargs.get('outer_thick') or SVG_OPTIONS['outer_thick']
        inner_thick = kwargs.get('inner_thick') or SVG_OPTIONS['inner_thick']
        path_color = kwargs.get('path_color') or SVG_OPTIONS['path_color']
        path_thick = kwargs.get('path_thick') or SVG_OPTIONS['path_thick']
        half = unit//2
        outer_lines = 'M 0 0 L '
        inner_lines = 'M {} {} L '.format(unit, unit)
        path = 'M {} {} '.format(half, half)
        path += 'L {} {} '.format(unit+half, half)
        square = self.squares[Vector(1,0)]
        while square.pos != Vector(0,0):
            x = square.pos.x * unit
            y = square.pos.y * unit
            path += '{} {} '.format(x+half, y+half)
            move = MOVES[square._in + square._out]
            # inner walls:
            if move != 'r':
                start_x = x + (0 if square._out in 'rd' else unit)
                start_y = y + (0 if square._out in 'ld' else unit)
                end_x = start_x + (0 if square._out in 'ud' else (unit if square._out=='r' else -unit))
                end_y = start_y + (0 if square._out in 'lr' else (unit if square._out=='d' else -unit))
                if move == 'L':
                    inner_lines += '{} {} '.format(start_x, start_y)
                inner_lines += '{} {} '.format(end_x, end_y)
            # outer walls:
            if move != 'L':
                start_x = x + (0 if square._out in 'ru' else unit)
                start_y = y + (0 if square._out in 'rd'else unit)
                end_x = start_x + (0 if square._out in 'ud' else (unit if square._out=='r' else -unit))
                end_y = start_y + (0 if square._out in 'lr' else (unit if square._out=='d' else -unit))
                if move == 'r':
                    outer_lines += '{} {} '.format(start_x, start_y)
                outer_lines += '{} {} '.format(end_x, end_y)
            square = square.next()
        path += 'Z'
        outer_lines += 'Z'
        inner_lines += 'Z'
        svg = '''
<svg id="svg" version="1.1" baseProfile="full" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ev="http://www.w3.org/2001/xml-events" width="{}" height="{}">
    <defs>
        <linearGradient id="linear1" x1="0%" y1="0%" x2="100%" y2="100%">
            <stop offset="0%" stop-color="#05a"/>
            <stop offset="100%" stop-color="#0a5"/>
        </linearGradient>
    </defs>
    <style>
#outer {{
    stroke: {};
    stroke-width: {};
    fill: transparent;
}}
#inner {{
    stroke: {};
    stroke-width: {};
    fill: transparent;
}}
#path {{
    stroke: {};
    stroke-width: {};
    fill: transparent;
}}
    </style>
    <g id="glyph" transform="translate({},{})">
        <path id="path" d="{}" />
        <path id="outer" d="{}" />
        <path id="inner" d="{}" />
    </g>
</svg>'''.format((self.size.x+1)*unit, (self.size.y+1)*unit, outer_color, outer_thick, inner_color, inner_thick, path_color, path_thick, unit/2, unit/2, path, outer_lines, inner_lines)
        return svg