This is a transverse flute, or french flute, meaning played horizontally.
Appropriately, the manufacturer used sliver-colored paint.
Unlike many depicions of woodwinds, the detail here is accurate rather than simplified.
There are actually two trombone images on this pencil,
one sort of piggybacking the other.
So from this vantage point, you can get the full picture between the two of them.
You get the detail right down to the water key, commonly known as the "spit valve."
A partial spectrum is shown on this pad, which depicts two of the most recognizable symbols in music:
The G clef sign on a staff, making this a a treble clef setup.
There is also a repeat sign, of sorts; the two dots should be followed by two vertical lines.
This memo pad is "headed" by a conductor, as is a typical symphony orchestra.
It enables the notemaker to write on the lines of four staves, organizing the message into four paragraphs!
Perfect for grocery lists, this pad features three Canadian musicians.
It's possible that the cartoonist was working from a reversed image,
since the sax players hands are switched and the guitarist is backward.
Don't even ask me to make sense of of the clarinet player's hand position.
One of my guitar students used to make memo pads for me every year.