"Inclined plane with triangle" is a cumbersome name for what in its end position is a picture-perfect kind of Cross -- this ability to hold stable in a horizontal arc while lifting vertically up. It is so strenuous to lift one's body out of the heaviness of Earth, out of emotions, out of the daily strains and stresses that accumulate over the weeks, months, years.
It's not just about strength, but balance, too; the ability to balance both the horizontal and the vertical, to balance the tangible work-at-hand on Earth and the the invisible work of an open consciousness, and to balance the experience of any Life-event or situation and our emotional response to it. Sometimes it is our emotions, rather than the actual event itself, that cause the most damage and pain to ourselves and others. It is so important to remember that our soul/mind/personality -- whatever you want to call it -- is not at all dependent on these psychological emotions that come out of the body.
It doesn't mean we attempt to bliss out though or find some means to escape Earthly life and our duties on this plane. Vasisthasana is the Sanskrit word for this pose, named after an Indian sage Vasistha who encouraged Lord Ram not to run away from his emotions born out Earthly troubles, but to become aware of these impressions and experiences of the body. We are then able to experience life in a free way. Our consciousness becomes more receptive, and our material body, while solid, radiates aliveness.