3D Printed Donut Utility Holder

Above: Design shown in profile

Challenge: To create a piece of utilitiy holder suitable for holding pens/pencils (but also have the potential as a general holder of items).  Student who created this is a Y5 student, nine years old in her first year of using 3D Printing.
Background: Student has shown some creation and invention with various projects related to 3D Printing in the classroom.  Student is designing a series of prints and creation and conferencing with the teacher with regards to their originality and purpose.   This design, while it would appear complicated comes primarly from the main Tinkercad Interface, which has a series of basic designs that students can take and reshape, redesign and ensure that they meet the criteria for the purpose set above in the challenge.
Level of Difficulty: Low - while the design is exactly what the student had in mind (see below) the essential issue here was the redesigning of the shape created by Tinkercad and ensuring that it was able to meet the purpose.  In this case the student needed to redesign the shape to meet the purpose of holding pencils and general items that the student wanted to store in it.    The size, relative to the design, was perfect for the design.

Above: Original design as shown as an .STL download file

Timeframe: Twelve hours - consideration could have been given for the infill used in this design, to reduce the density of the print to still complete the purpose.  Every design on this site, has always used the basic default settings for the infill, most printing software will allow you the opportunity to alter the level of filling it.   The default setting on the CURA software (which is the Ultimaker 2 in-house software) is at 20%.   It creates a series of connected lines in a crosshatch form which prove to be the strength of the object.  We have not experimented with reducing this infill, however the strength of the prints featured on this site have not been in question, as we have (after three years) yet to have significant damage to the produced items, which seem to be extremely durable and robust.
Size: The width of this desing was 100mm.   The height of the design was 100mm.   The width of the design was 25mm at the top. Conceivable the width of the design could have been reduced to reduce the length of printing time.
What we would do differently:   The student obviously missed an opportunity to personalise the container with their name or the purpose of the container (however the student was adamant that they wanted this container to be multi-purpose and not restricted to one purpose as it would have been if it was created with a label).
Next steps for students: To show other students (and teachers) how to produce material/projects of a similar nature.  This student has mastered this type of project and needs to extend herself in other ways.