Learn Abstract and Concrete with Small Basic

I wrote some programs for learning abstract and concrete.  At first I made a subroutine Average().  This routine calculates (a + b) / 2.  The concept average is a special (concrete) case of a wider concept.  Secondly, I made a subroutine Intermediate().  The concept of this routine is wider and more abstract than Average().  Intermediate() needs one more parameter k.  And if k = 0.5, the result is the same as Average().  The output of this program is:

Average(a=10, b=20) = 15
Intermediate(a=10, b=20, k=0) = 10
Intermediate(a=10, b=20, k=0.25) = 12.50
Intermediate(a=10, b=20, k=0.50) = 15.00
Intermediate(a=10, b=20, k=0.75) = 17.50
Intermediate(a=10, b=20, k=1.00) = 20.00

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The code is here.

I sometimes use the code like Intermediate(). So I also wrote application samples of Intermediate() for points and colors. The program ID is HRX565-0.  This program is also text base.

One more sample is HRX565-1.  This is a graphical demo animation program for these concepts.