Is the grammar you used for the piece simple or complex?

It's simple. For the piece, I used the following simplest L-system:

n = 0 : A
n = 1 : AB
n = 2 : ABA
n = 3 : ABAAB
n = 4 : ABAABABA

The piece consists of six sections as follows:


0.00 0.10    1'55''  3'47''  5'35"   7'21"   9'06"    11'10"
　　　|   A   |   B   |   B'  |   C   |   A'  |   B''  |


Each section was generated as a MIDI file by my Java program. Being
assigned different mean values of Poisson distributions, the Java
program first calculated the numbers of the occurrences of
transformations by six different intervals. section B, for example,
consists of the following numbers of the occurrences of transpositions
of pc-sets:

The number Of T6's = 0
The number Of T11's = 3
The number Of T9's = 3
The number Of T4's = 4
The number Of T2's = 4
The number Of T7's = 10

while, Section C, assigned a different mean value, has the following
distribution of transpositions:

The number Of T4's = 2
The number Of T9's = 2
The number Of T6's = 3
The number Of T11's = 5
The number Of T2's = 5
The number Of T7's = 7

Because section C has more T11's (transpositions by interval 11 (11
semitones)) and T6's than section B, it sounds more dissonant and tense
than Section B.

Then the Java program distribute those transpositions throughout a
section following a pattern generated by an L-system:

Level
  1    B
  2    A
  3    A         B
  4    A     B   A
  5    A   B A   A   B
  6    A B A A B A B A

where all the instances of each transposition are assigned to B's at a
certain level. At the next level, those B's become A's, new B's occur,
and the A's keep holding the same transpositions assigned at the
previous level until the last level.

As a result, in section B, for example, the transpositions are arranged
as a sequence as follows:

T: 7 2 4 7 9 7 2 11 7 2 4 7 7 2 4 7 9 7 7 7 4 9 11 11

and, in section C:

T: 7 2 11 7 6 7 2 9 7 2 11 7 4 7 2 11 7 6 2 11 6 9 11 4

Note that both series show some recurrent patterns. You can change
patterns in different ways. For example, you can change, of course, mean
values of the Poisson distribution, change the order of the assignments
of the transpositions to an L-system, use different types of L-systems,
and so on.

I have a funny story about my use of formal grammar such as L-systems. I
started getting interested in formal grammar in mid-90s when I was
trying to migrate from my black NeXT to a Linux machine. After building
my first Linux box, one of the first things I did with it was to run my
C program that generated PDM1. When I listened to the piece the Linux
box produced, I was stunned. "It's an entirely different piece and it
sounds so bad!"

I suspected that it had to do with the rand() function. So, because I
couldn't find the source code of the C libraries on my NeXT, I went to
Akihabara and bought a CD of BSD Unix (4.4BSD-Lite2) (the Internet was
not first enough) and found the following code:

long rand() throws Exception {
seed = (seed * 1103515245 + 12345) % (0x7fffffff + 1);
return seed;
}

Taking a look at this function, I understood for the first time why PDM1
had nice recurrent patterns of melodies and harmonies. That's because of
the rather short periodicity of a series of random numbers. In my old C
program, rand() was called many times not only to produce
Poisson-distributed random numbers but also to choose pitches.

So, the piece produced by the Linux machine was different because the
rand() functions were different. The PDM1 produced by the Linux machine
sounds just like a random series of notes, which results from the much
better rand() function with much longer periodicity.

So, I started trying to find a way to produce nice recurrent patterns
without relying on the short periodicity of a rand() function and have since done a lot of experiments with formal grammar.

Now that I can use almost any formal grammar in my Java program, I feel
that I'm in possession of materials sufficient for the pieces I'm going to
compose for the next few years. :)

Also, the movie seems black-and-white, but it looks like the jpg
image  has a lot of color.

The monochrome video was projected on the screen by four projectors and
mirrors and, in addition, filtered laser beams and LED lights are
projected on the screen as well. The colors on the screen are those of
the live lasers and LEDs.