The first one is easy to make/split. Choose the single vertex A, and then under Actions choose Merge to nearest edge and split.
The second is a little bit more tricky. Select vertices B and C and then press Alt V to create a new vertex between them.
But it has to be adjusted, since it is created in the exact middle between B and C. Then repeat and adjust for the others.
Image 008.png (Size: 34.94 KB / Downloads: 32)
Or, delete all the yellow triangles, position the Manipulator in A and copy / paste the orange triangles mirrored.
Use Actions, Scale selection and set -1 on the axis of your choise. Unselect the other axis.
The second is a little bit more tricky. Select vertices B and C and then press Alt V to create a new vertex between them.
But it has to be adjusted, since it is created in the exact middle between B and C. Then repeat and adjust for the others.
Image 008.png (Size: 34.94 KB / Downloads: 32)
Or, delete all the yellow triangles, position the Manipulator in A and copy / paste the orange triangles mirrored.
Use Actions, Scale selection and set -1 on the axis of your choise. Unselect the other axis.