54 Trans. Acad. Sci. of St. Louis. 



can be arranged in the form of regular polygons of 

 o A r^ sides for the respective cases, thus : 



O, '*, «', . . • ' 



1 3 



A 



<> 



5 



6 



A 



9 



12 



10 



16 



22 



^S ^ 



15 



A A 



25 



35 



6 15 



1 7 



1 8 



18 



O fO^ 



Y_^/ 



21 



O (O) 



28 



01 



40 



