Guess Beethoven's Strings app for iPhone and iPad

Ludwig van Beethoven (1770 – 26 March 1827) was a German composer and pianist. A crucial figure in the transition between the Classical and Romantic eras in Western art music, Beethoven is often cited as the greatest composer who ever lived.
Born in Bonn, then the capital of the Electorate of Cologne and part of the Holy Roman Empire, Beethoven moved to Vienna in his early 20s, studying with Joseph Haydn and quickly gaining a reputation as a virtuoso pianist. His hearing began to deteriorate in the late 1790s, yet he continued to compose, conduct, and perform, even after becoming completely deaf.

Sonata, from Latin and Italian: sonare, "to sound", in music, literally means a piece played as opposed to a cantata (Latin and Italian cantare, "to sing"), a piece sung. The term, being vague, naturally evolved through the history of music, designating a variety of forms prior to the Classical era. The term took on increasing importance in the Classical period, and by the early 19th century the word came to represent a principle of composing large scale works. It was applied to most instrumental genres and regarded alongside the fugue as one of two fundamental methods of organizing, interpreting and analyzing concert music. Though the musical style of sonatas has changed since the Classical Era, most 20th- and 21st- century sonatas still maintain the same structure.
******************************************************************
This app contains 15 puzzles. The puzzles are in the form of 10 sonatas for Violin and 5 sonatas for Cello composed by Beethoven.

I - Opus 12 No. 1: Violin Sonata No. 1 in D major
II - Opus 12 No. 2: Violin Sonata No. 2 in A major
III - Opus 12 No. 3: Violin Sonata No. 3 in E-flat major
IV - Opus 23 Violin Sonata No. 4 in A minor
V - Opus 24 Violin Sonata No. 5 in F major (Spring)
VI - Opus 30 No. 1: Violin Sonata No. 6 in A major
VII - Opus 30 No. 2: Violin Sonata No. 7 in C minor
VIII - Opus 30 No. 3: Violin Sonata No. 8 in G major
IX - Opus 47 Violin Sonata No. 9 in A major (Kreutzer)
X - Opus 96 Violin Sonata No. 10 in G major (The Cockcrow)
XI - Opus 5 No. 1: Cello Sonata No. 1 in F major
XII - Opus 5 No. 2: Cello Sonata No. 2 in G minor
XIII - Opus 69 Cello Sonata No. 3 in A major
XIV - Opus 102 No. 1: Cello Sonata No. 4 in C major
XV - Opus 102 No. 2: Cello Sonata No. 5 in D major