Because the wavetable technique implies a circular buffer, output signals are inherently periodic (assuming a relatively constant phase increment).
More complex periodic signals can be generated with wavetable synthesis by computing a waveform using additive synthesis. For example, we could easily add a weighted sinusoid to the table shown in Fig. 1 that completes 2 cycles in 64 samples (or other higher integer multiples).
When making use of wavetables with more complex frequency content, one must be careful when adjusting the phase increment to avoid aliasing.