There are two pickups in 'Iterate', pickups are small black squares.1. Level 6.2
In this level you need to follow the ray of light to the switches, after you press the second switch the pickup will be above the middle block, you will need to double jump at the peak of your first jump to reach it
.2. Level 6.7
This ones easy, at the start of the level switch to Sarah and head towards the middle of the level, the pickup is just above the floor spikes, you will die getting this.
Here's a video