Vijnana Bhairava Tantra · Dharana 36 · Verse 59
Bowl without partitions
Look at a bowl, a cup, or any vessel. The mind wants edges: rim, wall, hollow, handle. Keep looking until those divisions lose their authority and the whole thing is one space. The object can stay visible. What drops away is the habit of cutting it into parts. Stay when only space is left, even if the cup is still on the table.
Older line
Cast your gaze into a pot or any vessel, leaving aside its walls. At the moment the mind dissolves into the space within, you become that space.