For your fantasy castle design using spruce wood and deepslate, consider the following ideas:

Castle Layout:

• Main Structure: A large central keep made primarily of deepslate, featuring intricate carvings and large arched windows. The keep can be surrounded by a wooden palisade made of spruce wood for a contrasting texture.

Towers:

• Small Towers: Incorporate four small towers at each corner of the castle, constructed from deepslate with spruce wood accents. Each tower can have a conical roof made of spruce slabs and a small balcony for aesthetic appeal.

Gardens:

• Garden Areas: Design multiple small gardens within the castle walls, using a mix of flowers, bushes, and pathways made from gravel or cobblestone. Consider adding benches and decorative fences made from spruce wood to enhance the garden's charm.

Wall Design:

• Surrounding Wall: Create a circular wall extending from the castle, using deepslate for durability and spruce wood for decorative elements. The wall can be about 5 blocks high with crenellations for a fortified look, allowing for a clear view of the surrounding area.

Interior Features:

• Courtyard: Inside the walls, design a spacious courtyard that can host additional structures such as stables, workshops, or even a small marketplace, all made from spruce wood to maintain a cohesive theme.

This design will provide a grand and immersive fantasy castle experience while allowing ample space for additional builds within the circular area.