Look, you got a few tips on what command to use to do some geometry modelling. The documentation is really good and the few tips I gave you should have been enough to get you started. Below is some APDL-code to generate a model similar to yours. Step through the commands line by line so you will understand what is happening. [pre]/prep7
ET,2,MESH200
KEYOPT,2,1,6
KEYOPT,2,2,0
/pnum,kp,1
/pnum,line,1
/pnum,area,1
/PSYMB,LDIV,1
csys,1
k,10,.5,0
*repeat,4,1,,90
k,20,1,0
*repeat,4,1,,90
/replot
gplot
l,20,21
l,21,22
l,22,23
l,23,20
/replot
csys,0
l,10,20
*repeat,4,1,1
l,10,11
l,11,12
l,12,13
l,13,10
/replot
al,1,6,9,5
*repeat,3,1,1,1,1
al,5,12,8,4
a,10,11,12,13
gplot
lsel,s,,,1,4
lsel,a,,,9,12
lesi,all,,,12
lsel,inve
lesi,all,,,5
lsel,all
lplot
amap,4,13,23,20,10
amap,5,10,11,12,13
amap,1,10,20,21,11
*repeat,3,1,1,1,1,1[/pre]
BTW, creating a line between two KPs in a cylindrical csys will create an arc.