Tensift · Ten cards. Four groups. One hidden rule.
Musical instruments
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This page contains the answer to a past puzzle. Today’s puzzle is separate.
Drum · Trumpet · Trombone · Flute · Clarinet · Oboe · Violin · Guitar · Cello · Harp
Listen to how the sound begins
The most useful starting contrast is between the drum and the instruments with vibrating strings. The drum stands alone in this selection, while violin, guitar, cello and harp fill the four-card row. Those counts suggest a familiar instrument-family convention.
The remaining five all involve air, but one five-card group will not fit. Trumpet and trombone form the pair; flute, clarinet and oboe form the trio. A good rule explains why that split is meaningful, rather than simply using row sizes to force unrelated cards together.
Why the material can mislead
A metal flute does not move into the brass family just because of its material. In this convention, the way sound is produced matters more than the substance of the instrument’s body. That is why “made of metal” is a poor replacement for the intended rule.
The string row also contains different playing techniques. Guitar and harp are commonly plucked; violin and cello are commonly bowed. Separating by those techniques would answer a narrower question and would break the four-card group.
Use the convention at the right level
These are familiar instrument families, not a comprehensive catalog of every instrument or every acoustical classification system. The selected cards avoid instruments such as the piano, which can invite discussion about strings, striking actions and keyboard groupings.
When evaluating an alternative answer, ask whether the same level of description applies to every row. A family in one row and a playing technique in another would mix levels. Carry this check into the next puzzle: keep both the property and its level of detail consistent.
The grouping
Each group is an instrument family: 1 percussion instrument, 2 brass instruments, 3 woodwinds, and 4 string instruments.
- 1 · Percussion
Drum
- 2 · Brass
Trumpet · Trombone
- 3 · Woodwind
Flute · Clarinet · Oboe
- 4 · Strings
Violin · Guitar · Cello · Harp