Usage
left_border_color(ht)
left_border_color(ht) <- value
set_left_border_color(ht, row, col, value )
map_left_border_color(ht, row, col, fn)right_border_color(ht)
right_border_color(ht) <- value
set_right_border_color(ht, row, col, value )
map_right_border_color(ht, row, col, fn)
top_border_color(ht)
top_border_color(ht) <- value
set_top_border_color(ht, row, col, value )
map_top_border_color(ht, row, col, fn)
bottom_border_color(ht)
bottom_border_color(ht) <- value
set_bottom_border_color(ht, row, col, value )
map_bottom_border_color(ht, row, col, fn)