佛說觀佛三昧海經 7.31

7.31

Then the Bhagavat manifested five hundred jeweled chariots, and the Buddha, dwelling in the chariots, divided his body into five hundred. The jeweled chariots then remained in the sky, turning freely. Between the chariot hubs and rims were hundreds of thousands of rays of light, and within each ray were countless transformation Buddhas. Without moving or turning, he arrived at the city of Kapilavastu, sat on the lion throne as if entering samādhi, and from one pore a Buddha emerged; into one pore another Buddha returned. Thus emerging and entering, boundless transformation Buddhas sat cross-legged filling the sky. This is called the realm of the Tathāgata while sitting.
After the Buddha's parinirvāṇa, if the Buddha's disciples wish to know the Buddha's walking, it is as spoken above; if they wish to know the Buddha's sitting, they should contemplate the Buddha's shadow. Those who contemplate the Buddha's shadow should first contemplate an image of the Buddha, imagining it to be sixteen feet high, sitting cross-legged with grass spread as a seat, inviting the image to sit. Having seen it sitting clearly, they should further form a visualization: visualize a rock cave, eighteen feet high, twenty-four paces deep, visualized as clear white stone. When this visualization is achieved, they see the sitting Buddha image abiding in the sky, raining flowers beneath its feet. Again, they form the visualization of walking, entering into the rock cave. Having entered, they further cause the rock cave to be visualized as a seven-jeweled mountain. When this visualization is achieved, they again see the Buddha image leaping into the rock wall, the rock wall unimpeded like a bright mirror. When this visualization is achieved, as before, they again visualize the thirty-two marks, contemplating each mark so that it is extremely clear. When this visualization is achieved, they see transformation Buddhas sitting cross-legged on large jeweled flowers, emitting bodily light that illuminates everywhere. From the pores of the body of each seated Buddha rain an asaṃkhyeya of seven-jeweled banners. At the top of each banner are hundreds of thousands of jeweled pennants; the very smallest pennant is equal in length and breadth to Mount Sumeru. Within these jeweled pennants are countless hundreds of thousands of transformation Buddhas; each transformation Buddha leaps and enters the shadow and the navel of the Buddha in this rock cave. When this visualization appears, it is preached as from the Buddha's mind. One who contemplates thus is called one of right contemplation; if one contemplates otherwise, it is called wrong contemplation.