Let us remember Poosala naayanmaar today. He was born in a brahmana family and was a devout shiva bhakta. He wanted to build a shiva temple but did not have money for it. He could not collect money as well.
So he decided to build a temple in the mind itself. It was not an ordinary imagination but he carefully went through all details of building a temple in his mind. He will be in mauna most of the time and just go through all details meticulously
At the same time in kanchipuram, a king was also building a temple with bricks and mortar. Temple got completed and the king fixed the date for kumbhabhshekam. Poosala nayanar also completed his temple construction in the mind and fixed the same date as the king for his mentally
built temple. Shiva wanted to show to the world the greatness of poosalar and he appeared in the dream of the king and said he cannot come to the kings temple on kumbabhishekam as he has another temple to go to. He told that his devotee poosalar has built another temple
The king goes in search of poosala nayanar but does not find any temple in the place. At that time Shiva appears and does anugraham to both king and poosalar. Poosalar did not give up just because he did not have money but mentally thought about the temple all the time
Similarly there is a great krti by bhagavadpaadaa called shiva maanasa pooja where he offers everything to show in the mind itself. This is yet another facet of sanatana dharma where we can do even maanasika pooja
