A playing pool includes an upper ring, a middle ring and a bottom sheet made
from
a flexible and water-proof plastic sheet by thermal fusion. The upper ring is a
rolled hollow ring, and the middle ring and the bottom sheet are made from a sheet.
The middle ring has an upper side and a lower side to connect the upper ring and
the bottom sheet by thermal fusion to contain water. The middle ring is formed
from an integrated and elongated plastic sheet and formed with a plurality of trapezoids
that have a narrower upper side, a wider lower side and slant lateral sides to
mate different perimeters of the upper ring and the bottom sheet. Every two neighboring
trapezoids are bordered by a wedge type slit notch directing vertically from the
upper side to the lower side thereof. The two lateral sides of two neighboring
trapezoids are connected by thermal fusion to form the middle ring to contain water.
The integrated middle ring can enhance the resistant force against water pressure.
