Are stairs that rise from the middle and go to both sides proper?
Yes, they are perfectly fine; the palaces of kings and maharajas had stairs on both sides.
Related questions
A house has its entry in the Agni kon (South-East), an underground water tank in the South-East with the stairs over it, and the slope running to the South. The family fights constantly. What is the remedy?
Either leave the house or treat it: close the South-East underground water tank immediately and correct the slope. The staircase can stay. An overhead tank in the South-East is acceptable.
Are stairs made of mixed iron and plywood acceptable in the North?
Stairs should not be built in the North at all; if they must be, use wood. Many showrooms with wooden double-height staircases are found to do very well, because wood represents Mercury just as stairs and business do, so wooden stairs boost intelligence and keep business running.
Can a septic tank be placed under the stairs?
No, a septic tank does not work under the stairs.
Can a staircase be built in the East?
No. Nobody has the courage to stop the Sun's rays, and whatever blocks them is ruined, so no staircase or high structure in the East.
Can an overhead tank be built over the staircase?
Only if the stairs are in the North-West; otherwise not. Basically an overhead tank should not be built over the stairs, because hydro currents move as you walk below it and the mind becomes unsettled.
Can black granite steps be used for stairs in the North-West?
Use kota stone for steps in the North-West. Granite is best avoided in general, since it develops pin holes in which negativity settles.