Left, a favorite Spanish color scheme of blue, turquoise, yellow, and gold--also a favorite Moorish palette.
Below, a metal 4 has pleasing curves. And an almost unreadable 13 (?) challenges interpretation.
And these three were from tile, for house numbers in Toledo; very standardized but appealing, nevertheless.
I've collected several more numerals from Segovia. One is carved in granite, with both strength and elegance, on the base of a statue. Two are included simply for their color.