Shunyata; emptiness
Animittata; signlessness
Apranihitata; wishlessness
Among these Shunyata is most famous & well known, but now we turn our attention to Animittata or Signlessness. The source of yogachara is the meditation instructions on Signlessness. This means that a Sign is Dependent nature, paratantra; on it mind imagines all kinds of things, this is Imaginary nature, parikalpita; absence of signs is Truly Established nature; Parinishpanna; and it is also the door to liberation called Signlessness, animittata. Hence it is natural that the important cittamatra/yogachara sutra named Lankavatara speaks a lot about Signlessness.
Meditation instructions concerning Apranihitata or Wishlessness are the source of Mahamudra school and Mahamudra lineage, it is like an ultimate passivity, not changing or altering anything that appears, and so on. Thus there is also fear and dread toward the state of wishlessness, you have to make dozens of good wishes, dedication prayers and aspirations after a short meditation on wishlessness! Apranihitata has also been called directionlessness.
These three doors have caused the arising of different lineages and different schools of meditation instructions. They are a natural development that has arisen from the oral instructions of Bhagavan Shakyamuni.

