A simple paint technique with great result, and lots of possibilities to vary on the theme.
I wanted a flowerpot against the facade of my house, matching the mosaic the previous house owner glued to the wall. As you can see the mosaic tiles are dark blue, and there aren't many blue flowerpots. So I bought a straightforward grey clay-fiber pot and pimped it
Step 1: Preparation
Mixing some outdoor black wallpaint with artists acrylic in blue and green I achieved a nice dark blue color matching the tiles on the facade wall. I did not mix it quite thoroughly, so the paint result doesn't look flat, but shows some variation. Paint a few inches on the inside of the rim as it, may be, can be seen after planting.
Step 2: Line out the ornaments
Cut a circle from cardboard. Draw around it with pencil onto the pot. Space the circles evenly around the pot. Mine fitted five times. An odd number looks better than an even number. I choose not the fill the whole surface of the pot to make faux mosaic as it would blend too much with the wall. A mosaic rim around the pot was another option but as the wall has already a rim, it would be a little unimaginative. Hence the circle shape. It gives the pot a slight Japanese feel. A good combination with the little tree I planned to put in it.
Step 3: Create "mosaic"
Cut out pieces of masking tape. I used a blue professional masking tape witch is flat ( no crinkles), glues better an is more easily removed than the normal light brown version. Glue pieces against the pencil line and try to fill in the gaps with matching pieces. I choose not to fill the whole circle. The gap makes the pattern more unique and interesting. A repeating pattern is as wallpaper. A changing pattern with variations intrigues. Why these shapes, does it resemble something? Is it art?
Fill the gap with masking tape and put a rim around the circle with pieces of tape. Press all firmly down.
Step 4: Paint the grout
With a white acrylic paint dab between the pieces of tape. Any bulky structure of the paint, created by the dabbing adds to the cementy feel of the grout.
Note that if i had wanted a grey grout I would have used a "negative method". Put narrow strips of masking tape where I wanted the grouts, and paint the dark blue over that. After removing the tape revealing the original grey pot color in the grout space. I posted a Giraffe table instructable some time ago witch explains this in further detail.
Step 5: Peel of the tape
When the white paint is almost dry, remove the tape. Start with the outside rim and the big piece in the center. One by one remove the little pieces. Take care not to smudge the paint. On the other hand it is not to be advised to wait until the paint is completely dry. You could then sometimes lift the paint of together with the tape.
Step 6: Design different motifs
Not much designing has got into it. I just pasted pieces of tape inside the circles and let the shape grow. But to create some deliberate diversity I made different gaps in the outline, sometimes wide, sometimes narrow and sometimes not at all. One zigzag lightning across the circle, and two "beasts" inside. If you to make these kind of patterns, I think you better not copy but keep ideas like the zigzag, beast, outline gap etc in mind and see where it brings you.
Note that these design are not possible with real mosaic. It adds to the interest. Looks like mosaic, but, can't be, how did he...?