I posted an article,Photo Essay on the nine sleeping poses of Vishnu.
Lord Vishnu does not sleep.
His sleep is called Yoga Nidra (Sleeping posture i Yoga) or Ari Thuyil(Tamil–sleeping while aware of everything)
The Snake Adisehsa is the coiled Cosmic energy in the Solar Plexus(Mooladhaara).
The Ksheera Saagara is a representation of the Milky way Galaxy.
Please read my Post Vishnu’s’ Conch and Discus in galaxies, filed under Hinduism/Astrophysics.
This Yoga Nidra of Lord Vishnu is of Nine types.
1.Vadabadra Sayanam, Srivilliputtur.Moolavar Image not available.
I had written on the sleeping, floating Visnu in Budhanikantha Nepal.
I have been under the impression that the Anathasyana form of Vishnu found in Srivilliputhur, Sri Rangam and Thiruvanathapuram are the largest, in that order
I am wrong.
There is a Rock Cut Anantha Sayana Vishnu in the Village Sarangi in Odisha.
Anantashayi Vishnu, also known as Anantashayana Vishnu (both literally “sleeping on the serpent Shesha”), is a large open air rock-cut image of the Hindu god Vishnu, carved during the early 9th Century in the Saranga village, under the Parjang police station, in Dhenkanal district of Orissa, India. It is located on the left bank of the Brahmani River. It is the largest such exposed rock cut structure in the horizontal position measuring 15.4 metres (51 ft) in length, in the whole of India, while the largest standing image is of Gomateshwara in Southern India. It is a protected monument maintained by the Archaeological Survey of India, BhubaneswarCircle. Worship is still offered to the four armed reclining Vishnu.
The Vishnu image, under the open sky, occupies an area measuring 15.4 metres (51 ft) in length and 7 metres (23 ft) in width with a thickness of 0.7 metres (2 ft 4 in). The image is of the Hindu god Vishnu in a reclining position (Anantashayana in Sanskrit, literally sleeping on the serpent Ananta). The image is carved out of natural rock of sandstone formation. He has four arms, holding a Chakra in the upper right hand, a Shankha in his upper left hand, a Gada and a symbolic lotus on its lower left hand. The hoods of the serpent Shesha (Ananta) covering the head of Vishnu.The Vishnu image has a sharp chin, distinctive nose and wears a crown on its head, called kiritamukuta (a tall conical crown, typically worn by Vishnu). A lotus design shown sprouting from his navel has the creator god Brahma, sitting in meditation. Another image in the same district also carved in sandstone in a reclining posture is in Khamkanaga Subdivision, in Angul district of 41.5 feet (12.6 m) length (as against the length of 15.4 metres (51 ft) image in Saranga village.The sculptor has imagined the river bank conceptually to represent the Kshirasagara (cosmic ocean) from which Brahma created the world. The shrine is regularly worshipped by local people. The Archaeological Survey of India is renovating this sculpture regularly and has kept it in a good condition. Floods in Brahmani River are the only threat to the image as this is built by sandstone in the river bed, which could erode.
The Vishnu image, located on the left bank of the river bed of the Brahmani River, is at an elevation of 200 feet (61 m). It is accessible by road over a distance of 1.5 kilometres (0.93 mi) from Saranga Village in Parajanga Tehsil of Dhenkanal district, 67 kilometres (42 mi) from Dhenkanal, 23 km from Angul and 3 kilometres (1.9 mi) from Talcher. It is also approached from theNational Highway 42 from Cuttack to Sambalpur, on branch road over distance of 3 km. The second natural rock-cut image in parent rock is at Bhimakand in Talcher subdivision of the Dhankal district.