Question: How to save data in vectors ?

HI folks ! I'm new to this forum and I have a problem with the Euler Method to solve equations.

In the method, there are 3 variables, x, v and t. I need to save the result from every step from the method of the 3 variables and then create a matrix with 3 columns (one for each variable) and any amount of lines.
Is is the best way to do it ? I'm having a lot of trouble at storing data into vectors. 

To clarify my problem, here is my program:

restart; 

dt := 0.1e-2;

 xo := 1; vo := 0; vec := [xn, vn, t]; omega2 := 1;] i := 1;

 for i to 1000 do i 

xn := xo+vo*dt; 

vn := vo-omega2*xo*dt; 

t := i*dt; 

xo := xn; 

vo := vn;

 xf := [op(vec), [xn]];

 vf := [op(vec), [vn]]; 

tf := [op(vec), [t]] 

end do;

> B := Matrix([xf, vf, tf]);

In the Matrix B, after storing the vectors into it I have only 3 lines filled instead of 1000 (i). And another problem is that in the 3 lines, each column has the same value. It's appearing like this:

[[0.5405728050,-0.8418916460,1.000,[0.5405728050]],[0.5405728050,-0.8418916460,1.000,[-0.8418916460]],[0.5405728050,-0.8418916460,1.000,[1.000]]]

I really don't know what to do. So, any help to solve my problem or another method to do the same would be really great ! Thanks alot !