Use one transistor in a phase-shift oscillator configuration and chose
your components for the same waveform ;-)

While you may not get the same effect or knowledge of building the circuit
there are some ICs that will do that in one small package.
Even the one transisitor oscillators are good enough for learning the
code.
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Indeed a single transistor 'double Tee' phase shift oscillator with a single
chip audio amp ,if you wish to use a loudspeaker , + a key is all you need
to learn /practice morse code.
It is a popular 'very simple project' candidates for the UK Intermediate
Licence can choose to do .
At the moment candidates for this AR licence have to construct something
simple in order to be assessed for basic construction/soldering skills.

Frank GM0CSZ / KN6WH