the modular construction system includes identical shell bodies 1 , such as that shown in fig1 . each shell body is shaped as a cylindrical container for an application - specific filling 2 . according to the type of shell to be constructed , the shell body 1 is closed by one of an application - specific selected shell head 3 , 3 ′, 3 ″ ( for example , screwed on , latched on , or glued on ) as shown in fig2 - 4 , respectively . for explosive shells , a fragmentation filling and explosive filling are used , and a shell tip 3 of metal or a thermoplastic material is placed , preferably with a rubber - type bearing , on the shell body 1 as shown in fig2 . corresponding explosive shells 4 , 5 are shown on the left - hand side of the drawing . fig3 shows four non - explosive shells 6 , 7 , 8 , and 9 . these are composed of the shell body 1 , the application - specific filling 2 ( ballast , flare compound , tear gas , detonation charge , marking dye , marking dye with light trace , smoke compound ), and shell head 3 ′ formed of plastics material . the plastics shell head 3 ′ has ray - shaped pre - determined breakage points 13 . fig4 shows three non - explosive shells 10 , 11 and 12 . these shells include shell body 1 , the desired filling 2 ( ballast , flare compound , tear gas , detonation charge , marking dye marking dye with light trace , smoke compound ), and shell head 3 ″ formed of plastics material . the plastics shell head 3 ″ has additional grooves around the periphery . fig5 illustrates various manners in which the shell head 3 , 3 ′ 3 ″ can be connected to the shell body 1 . in particular , fig5 b shows a thread 15 at the edge of shell body 1 onto which the shell head 3 , 3 ′, 3 ″ is screwed . alternatively , fig5 c shows an annular bead 16 at the edge of shell body 1 onto which the shell head 3 , 3 ′, 3 ″ can be snapped . although only head 3 ″ is shown in fig5 these connections are also applicable to shell heads 3 , 3 ′.