From sketch to piece: unity and contrast – free course

Every composer knows this moment: you have found two wonderful bars… and you have no idea what to do with them. Beethoven filled whole notebooks with sketches before building a sonata. This lesson shows you, step by step, how to go from a two-bar seed to a complete 24-bar piece in ABA form. The guiding principle: unity (everything grows from the same seed) and contrast (the seed transforms enough that the ear never gets bored).

Step 1: the seed

Here is our motif in 3/4: a descent E–D–C followed by a drop of a fourth, then a little neighbour figure A–G. It is short, singable and easy to recognise.

M:3/4
L:1/8
Q:1/4=100
K:C
e2 dc G2 | A4 G2 |]

Before writing anything else, analyse your seed: its rhythm (quarter, two eighths, quarter / half, quarter), its intervals (step, step, falling fourth), its contour (descending). Each of these elements is a resource you can develop later.

Step 2: phrase A

State the seed, then repeat it one step higher (a sequence), slightly altered so that it ends on the dominant. Dress it with a waltz bass: C, F, D minor, G.

M:3/4
L:1/8
Q:1/4=100
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "C"e2 dc G2 | "F"A4 G2 | "Dm"f2 ed A2 | "G"B4 G2 |]
[V:LH] C,2 [E,G,]2 [E,G,]2 | F,,2 [A,,C,]2 [A,,C,]2 | D,2 [F,A,]2 [F,A,]2 | G,,2 [B,,D,]2 [B,,D,]2 |]

These 4 bars form a "question" (half cadence). Repeat them with a conclusive ending and you have an 8-bar A section.

Step 3: section B, same seed, different face

For contrast, don't look for a brand-new idea: transform the seed. Here it is inverted (it rises instead of falling: C–D–E–A), we move to A minor, and the left hand drops the waltz for sustained bass notes. The character turns dreamy and dark, yet the ear senses the family resemblance.

M:3/4
L:1/8
Q:1/4=88
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "Am"c2 de a2 | "E"^g4 a2 | "F"f2 ed c2 | "E"B4 ^G2 |]
[V:LH] A,,6 | E,,6 | F,,6 | E,,6 |]

Step 4: the overall plan

Before writing more, draw the map of the piece. This table is your contract with yourself:

Bars	Section	Key	Material	Section ending
1–8	A	C major	Seed + sequence, waltz bass	Perfect cadence in C
9–16	B	A minor	Inverted seed, sustained bass, slower	Half cadence on E major
17–24	A'	C major	Return of A, climax at bar 21, broadened cadence	Perfect cadence + held final chord

Note the proportions: three equal 8-bar sections, with the climax of the piece placed about two thirds of the way through (around bar 21, close to the "golden section" that many pieces respect intuitively). The climax should be the highest note and the most intense moment of the whole piece.

Step 5: the ending

In A', alter the end of the sequence so that it closes: instead of stopping on B (G major), the melody reaches B over a G7 chord and then settles on C.

M:3/4
L:1/8
Q:1/4=100
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "C"e2 dc G2 | "F"A4 G2 | "G7"f2 ed B2 | "C"c6 |]
[V:LH] C,2 [E,G,]2 [E,G,]2 | F,,2 [A,,C,]2 [A,,C,]2 | G,,2 [B,,F,]2 [B,,F,]2 | C,6 |]

Unity and contrast, the 70 / 30 rule: roughly 70% of what the listener hears should be "already known" (repeated, varied, derived from the seed) and 30% "new". Too much novelty and the piece sounds disjointed; too much repetition and it sounds thin.

Common mistakes: writing bar after bar with no plan (you get lost around bar 12); looking for a new idea for every section (the piece becomes a patchwork); placing the climax too early; or forgetting to vary the return of A, which becomes a mere copy-paste. One small change in A' (ornament, octave, broadened ending) is enough to show that the journey has taken place.

Your workshop

In the piano roll, invent a 2-bar seed. Write its analysis underneath: rhythm, intervals, contour.
Fill in a form table like the one in step 4 (sections, bars, keys, material, section endings) before writing anything else.
Write section A (8 bars) using repetition and sequence of the seed, with a steady accompaniment.
Write section B (8 bars) by transforming the seed: inversion, minor mode, different texture. End with a half cadence.
Write A', changing at least two things (octave, ornaments, broadened ending), and place the climax around bar 20–21. Copy everything into the ABC editor.
Check: can you show, for every bar, where it comes from in the seed? If so, your piece has real unity.