may be substantially similar or identical to height h and as shown in fig3 most or all of their surfaces 62a and 62b see fig4 and 7 may contact the side wall 18 to match more closely the support provided side wall 18 to the pressure of water w as a function of height h buttresses 38 additionally may be flared in depth as illustrated in fig2 and 3 such flaring results in buttress 38 having its minimum depth d 1 at its top 66 and its maximum depth d 2 at its bottom 70 also adjacent ground g with the depth increasing substantially continuously between top 66 and bottom 70 buttress 38 thus resembles in the side elevational view shown in fig3 a right triangle unlike brace 10 however buttress 38 of fig3 has solid sides 74a and 74b a solid face 78 and is truncated at top 66 surfaces 62a and 62b moreover function as flanges of buttress 38 the result is a unitary structure for buttress 38 that both provides greater and more uniform and continuous support for side wall 18 and has a sleeker profile than braces 10 furthermore for some embodiments of buttress 38 maximum depth d 2 does not exceed ten inches an amount significantly less than the distance typically thirty six inches from pool 14 that braces 10 protrude other dimensions of an exemplary buttress 38 include height between approximately forty two and sixty inches width of approximately four inches and a minimum depth d 1 of approximately two to four inches buttress 38 is usually made of metal such as galvanized steel but may be manufactured of other materials when necessary or appropriate the face 78 sides 74a and 74b and surfaces 62a and 62b.