3 Adeniums and 1 Pachypodium.
First up we have three hybridized Adenium obesum flowers with very different colors. How do they get so many colors?
1. A fairly standard, but very saturated, solid pink.
2. A crazy bi-color. Most 2-color Adenium flowers are center/edge colored, not striped like this.
3. This one is closest to the true species. And you can see the 2-colored with the petals being white towards the center and pink along the edges.
And then we have a very lovely solid yellow colored Pachypodium rosulatum flower.