Help! Drawing markers in a circle in specific location

I'm really new to MatLab and I've been given this code but my Lecturer didn't explain it at all!

cL=-5:2*pi/8:9; c=-20:2*pi/8:9; R=20; x1=[R*cos(c') R*sin(c')]; xL=[R*cos(cL') R*sin(cL')];

plot(x1(:,2),x1(:,1),'ko','MarkerSize',30)

I want to be able to move the markers so they stay in the circle formation but are placed on the left or right but I can't figure out how to do that at all!

Any help? Or just a walk through of what each bit means.

Thank you,

Becky

Answer 1

[KSSV]

clc; clear all ;
cL=-5:2*pi/8:9; 
% c=-20:2*pi/8:9; 
c = linspace(0,2*pi) ;
R=20; 
x1=[R*cos(c') R*sin(c')]; 
xL=[R*cos(cL') R*sin(cL')];
plot(x1(:,1),x1(:,2),'r')
hold on
plot(xL(:,2),xL(:,1),'ko','MarkerSize',30)
axis equal