080207.mw
I forgot to save the worksheet on this day, so I'm trying to recreate it from memory. Sorry about that. Here goes:
First, we were talking about lists and sets and data and points and so on. Sets are surrounded by {} braces and have no inherent order. A list is surrounded by [] and has a fixed order.

(1) 

(2) 
Both lists and sets can have anything inside them, including another set or list:
> 
{ 1, [4,5], 2, {3}, apple}; 

(3) 
We can represent a point in the plane as a pair of numbers. Here we have a list of points:
> 
data := [ [1,2], [2,4], [4,8], [5,10]]; 

(4) 
> 
plot(data,style=point); 
> 
plot(data,style=point,symbolsize=15,symbol=circle,color=blue); 
We'd like to see both the line and the points on the same graph. We can do this by assigning the plots to a variable, and then using the display command from the plots library to show them on the same plot.
> 
linepic:=plot(2*x,x=0..5):
pointpic:=plot(data,style=point,symbolsize=15,symbol=circle,color=blue): 
> 
plots[display]({linepic,pointpic}); 
Let's generate some data, and let maple find the appropriate line for us. We'll use the seq command, so first let's play with the command itself.

(5) 

(6) 
Now let's make some points on the line y=x/2
> 
pts:=[seq([x,x/2],x=0..10)]; 

(7) 

(8) 
> 
PolynomialInterpolation(pts,x); 

(9) 
> 
pts2:=[seq([x,x/2],x=0..5),[5.5,6.5],seq([x,x/2],x=6..10)]; 

(10) 
> 
PolynomialInterpolation(pts2,x); 

(11) 
> 
display(
[plot(pts2,style=point,symbolsize=15,symbol=circle,color=blue),
plot(PolynomialInterpolation(pts2,x),x=0..10)]); 
> 
display(
[plot(pts2,style=point,symbolsize=15,symbol=circle,color=blue),
plot(PolynomialInterpolation(pts2,x),x=1..11,y=10..20)]); 