In the group where I did my PhD, one of the professors would do this (but without pre-announcing). He would start with really basic questions and gradually buil

In the group where I did my PhD, one of the professors would do this (but without pre-announcing). He would start with really basic questions and gradually build up to more complex questions. This was great for two reasons: 1. it builds up large common ground for understanding; 2. if someone in a leadership position does this, others will not feel ashamed of asking questions that they think may be basic.