reference is made first to fig1 - 3 . these are three - sleeve pipe elbows having different angles of separation of coupling sleeves from a reference axis . fig1 is a 45 - degree three - sleeve pipe elbow 1 having three sleeves 2 with coupling axes 3 of the three sleeves 2 having a design angle of 45 degrees of circumferential separation from a reference axis 4 . the three sleeves 2 have inside peripheries that are designed for telescopic insertion and tube - coupling relationship of either cylindrical beams or second ends of two - sleeve pipe elbows which are described and shown later . the 45 - degree three - sleeve pipe elbow 1 can be described also as a three - way , 90 - degree pipe elbow . however , in order to describe a symmetrical relationship of sleeves 2 with different angles of separation , three - sleeve pipe elbows are described in relationship to angles of separation of coupling axes 3 from reference axes 4 instead of from other coupling axes 3 . all of the components of this invention can be made of the same or of variously different materials . for most purposes , however , polyvinyl chloride , commonly known as pvc , is recommended . standard pvc pipe elbows and pipe sections can be used for most applications . in fig2 a 30 - degree three - sleeve pipe elbow 5 has the same three sleeves 2 with coupling axes 3 having a design angle of 30 degrees of circumferential separation from a reference axis 4 . the angle of separation of the coupling axes 3 from the reference axes 4 can be less than or greater than the 45 degrees shown for the 45 - degree three - sleeve pipe elbow 1 in fig1 . in fig3 angle of separation is 60 degrees for a 60 - degree , three - sleeve pipe elbow 6 . the coupling axes 3 and the reference axes 4 are measured in relation to centrally intersecting elbow junctions 7 . reference is made here to fig4 - 6 . these are two - sleeve pipe elbows having different angles of separation between sleeve axes . in fig4 a first coupling sleeve 8 of a two - sleeve , 90 - degree pipe elbow 9 has a coupling axis 10 that is 90 degrees from a second coupling axis 11 of a second coupling sleeve 12 . the first coupling sleeve 8 has an inside periphery that is the same size as the inside periphery of the three sleeves 2 of the three - sleeve pipe elbows 1 , 5 and 6 which are designed to receive the same size of cylindrical objects . in fig5 a two - sleeve 60 - degree pipe elbow 13 has 60 degrees of circumferential separation between coupling axes 10 and 11 of first coupling sleeve 8 and second coupling sleeve 12 respectively . in fig6 a two - sleeve 120 - degree pipe elbow 14 has 120 degrees of circumferential separation between coupling axes 10 and 11 of first coupling sleeve 8 and second coupling sleeve 12 respectively . reference is made here to fig7 . a cylindrical beam 15 is employed to connect two - sleeve pipe elbows 9 , 13 and 14 or three - sleeve pipe elbows 1 , 5 and 6 . the cylindrical beam 15 can be a uniform - diameter pipe as shown . however , it functions as a beam . an outside periphery can be different between opposite ends and it need not have an inside periphery nor a uniform interior if it has an internal portion for purposes of this invention . cylindrical describes the ends and beam describes the functional nature of the cylindrical beam 15 that joins pipe elbows 1 , 5 , 6 , 9 , 13 and 14 variously in embodiments of this invention . in fig8 a cylindrical beam 15 is shown inserted in a sleeve 2 of a 45 - degree three - sleeve pipe elbow 1 directly . this is a first type of redundant joints for a first type of redundant structures . in fig9 second coupling sleeves 12 of three separate two - sleeve 90 - degree pipe elbows 9 are inserted into separate sleeves 2 of a 45 - degree three - sleeve pipe elbow 1 . cylindrical beams 15 are inserted into first sleeves 8 of the two - sleeve 90 - degree pipe elbows 9 . this is a second type of redundant joints for a second type of redundant structures . a fourth two - sleeve 90 - degree pipe elbow 9 is fitted onto an opposite end of one of the cylindrical beams 15 to indicate connection with another redundant joint . one of the two - sleeve 90 - degree pipe elbows 9 is oriented to an attitude in which the first sleeve 8 and the cylindrical beam 15 inserted into it are neither parallel nor perpendicular to either sleeve 2 of the 45 - degree three - sleeve pipe elbow 1 . this is achieved by rotation of the sleeve 12 in the sleeve 2 . in practice , none of the second sleeves 8 will be parallel or perpendicular to sleeves 2 . this circumferential orientation is employed selectively to form angles between joints for construction of structural assemblies and structural objects having redundant joints with select angles between edges and faces . reference is made here to fig1 - 12 . a pentagonal redundant joint 16 shown in fig1 has pipe elbows 9 with first sleeves 8 oriented outside of sleeves 2 by rotating second sleeves 12 inside of sleeves 2 , as shown and described in relation to fig9 to form angles of 108 degrees between cylindrical beams 15 that are inserted into the first sleeves 8 . the cylindrical beams 15 so positioned form five sides of a pentagonal structural assembly 17 shown in fig1 . this pentagonal structural assembly 17 can be used for a side of a dodecahedron in which cylindrical beams 15 which are shown not inserted into second sleeves 12 at one end are inserted into like pentagonal redundant joints 16 of additional pentagonal structural assemblies 17 . a cylindrical beam 15 and two pentagonal redundant joints 16 are common to each pentagonal structural assembly 17 in a dodecahedron that can be so formed . the first sleeves 8 of the pipe elbows 9 are shown oriented with open ends clockwise from the sleeves 2 in fig1 - 12 . these are right - handed redundant joints . reference is made here to fig1 - 15 . in fig1 , a left - handed joint 18 is shown with first sleeves 8 of the pipe elbows 9 with open ends facing counterclockwise . in fig1 , two each of the first sleeves 8 and cylindrical beams 15 inserted in them are oriented to 90 degrees apart for use in a square structural assembly 19 with left - handed joints 18 . remaining first sleeves 8 and cylindrical beams 15 inserted in them remain to be adjusted circumferentially to form angles as desired for use in other structural objects such as a cubical or pyramidal structure . fig1 illustrates a hexagonal structural assembly 20 with 60 degrees between cylindrical beams 15 that are inserted in first sleeves 8 of elbows 9 . the structural assembly 22 employs right - handed structural joints as described in relation to fig1 . consistent use of either left - handed joints as described in relation to fig1 or right - handed joints as described in relation to fig1 for an entire structural assembly 17 , 19 and 20 or other structural assemblies and structural objects made from them is essential . analog variation of angles between cylindrical beams 15 by rotation of second sleeves 12 in sleeves 2 of elbows 1 , as described in relation to fig9 makes possible a wide variety of structural assemblies . combining joints using elbows 1 with joints made with elbows having different angles of separation of coupling axes 3 from reference axes 4 such as illustrated with three - sleeve elbows 5 and 6 and two - sleeve elbows 9 , 13 and 14 , increases selection of structural assemblies and structural objects . representative of many furniture uses of this invention is a simple coffee table that is shown with a circular glass top 21 on three variations as shown in fig1 - 18 . in fig1 , a cylindrical beam 15 is extended from each of two sleeves 2 of three 45 - degree three - sleeve pipe elbows 1 to form three sets of bipod legs 22 . in fig1 , angle legs 23 are formed by two - sleeve 90 - degree pipe elbows 9 at ends of horizontal cylindrical beams 15 . in fig1 , a cubic structure 24 is formed by completing a plurality of structural assemblies 19 shown in fig1 and setting the circular glass top 21 on it . a new and useful redundant - joint structure and method having been described , all such modifications , adaptations , substitutions of equivalents , combinations of parts , applications and forms thereof as described by the following claims are included in this invention .
redundant joints for a wide variety of redundant - joint structures have three - way plumbing elbows with coupling sleeves into which two - way plumbing elbows are inserted and rotated to form an infinite variety of angles of joining edges or sides of structural assemblies bordered by cylindrical beams inserted into sleeves in the two - way elbows . the three - way elbows can have different angles for particular structures than employed for conventional plumbing uses . for other structures , the three - way elbows have the same or similar angles as those employed for conventional plumbing . two - way elbows with a coupling sleeve at one end and a pipe - sized opposite extension employed for particular forms also can have different or the same angles as employed for conventional plumbing .